Inequality in Immunization 2023

A special issue of Vaccines (ISSN 2076-393X).

Deadline for manuscript submissions: closed (28 February 2023) | Viewed by 71361

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Guest Editor
Department of Data and Analytics, World Health Organization, 20 Avenue Appia, 1211 Geneva, Switzerland
Interests: health inequality; monitoring; immunization
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Immunization Analysis & Insights (IAI), World Health Organization, 20 Avenue Appia, 1211 Geneva, Switzerland
Interests: immunization; vaccine delivery
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Department of Data and Analytics, World Health Organization, 20 Avenue Appia, 1211 Geneva, Switzerland
Interests: health systems; inequalities; social determinants of health
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Global Immunization Division, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30329, USA
Interests: immunization; vaccine delivery; life course

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GAVI, The Vaccine Alliance, Geneva, Switzerland
Interests: immunization; monitoring evaluation and learning
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Special Issue Information

Dear Colleagues,

While overall in the world, immunization rates stagnated prior to the COVID-19 pandemic, and declined in 2020 and 2021, this is neither uniformly the case for all types of vaccines, nor for all population sub-groups for any individual vaccine. Furthermore, the breadth of protection varies, with many countries lagging behind in the introduction of new and under-utilized vaccines, such as those against the Human Papilloma Virus (HPV) and seasonal influenza, to name a few. In this Special Issue, we will explore the latest evidence on various types of immunization across the life course at global, regional, national and subnational levels. We encourage submissions that explore various dimensions of inequality—such as economic status, subnational geographic regions, sex, maternal education—and other categories (like migrant status or occupation), or that shed greater analytical or methodological light on priority population subgroups, namely, populations facing gender barriers, rural residents, the urban poor, and populations living in conflict areas. We encourage submissions that compare various country contexts or that assess trends over time, and those that draw from geographies where the evidence has been limited to date, such as Low and Middle-Income Country contexts. Communications that describe the impacts of inequality monitoring of immunization are also welcome.

Dr. Ahmad Reza Hosseinpoor
Dr. M. Carolina Danovaro
Dr. Devaki Nambiar
Dr. Aaron Wallace
Dr. Hope L. Johnson
Guest Editors

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Keywords

  • health inequalities
  • immunization
  • life course
  • inequity

Published Papers (27 papers)

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Editorial

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5 pages, 235 KiB  
Editorial
Inequality in Immunization: Holding on to Equity as We ‘Catch Up’
by Devaki Nambiar, Ahmad Reza Hosseinpoor, Nicole Bergen, M. Carolina Danovaro-Holliday, Aaron Wallace and Hope L. Johnson
Vaccines 2023, 11(5), 913; https://doi.org/10.3390/vaccines11050913 - 28 Apr 2023
Viewed by 1886
Abstract
Immunization, hailed as one of the most successful public health interventions in the world, has contributed to major advancements in health as well as social and economic development [...] Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)

Research

Jump to: Editorial, Review, Other

12 pages, 1141 KiB  
Article
“Zero Dose” Children in the Democratic Republic of the Congo: How Many and Who Are They?
by Daniel Katuashi Ishoso, M. Carolina Danovaro-Holliday, Aimé Mwana-Wabene Cikomola, Christophe Luhata Lungayo, Jean-Crispin Mukendi, Dieudonné Mwamba, Christian Ngandu, Eric Mafuta, Paul Samson Lusamba Dikassa, Aimée Lulebo, Deo Manirakiza, Franck-Fortune Mboussou, Moise Désiré Yapi, Gaga Fidele Ngabo, Richard Bahizire Riziki, Cedric Mwanga, John Otomba and Marcellin Mengouo Nimpa
Vaccines 2023, 11(5), 900; https://doi.org/10.3390/vaccines11050900 - 26 Apr 2023
Cited by 3 | Viewed by 2200
Abstract
(1) Background: The Democratic Republic of the Congo (DRC) is one of the countries with the highest number of never vaccinated or “zero-dose” (ZD) children in the world. This study was conducted to examine the proportion of ZD children and associated factors in [...] Read more.
(1) Background: The Democratic Republic of the Congo (DRC) is one of the countries with the highest number of never vaccinated or “zero-dose” (ZD) children in the world. This study was conducted to examine the proportion of ZD children and associated factors in the DRC. (2) Methods: Child and household data from a provincial-level vaccination coverage survey conducted between November 2021–February 2021 and 2022 were used. ZD was defined as a child aged 12 to 23 months who had not received any dose of pentavalent (diphtheria-tetanus-pertussis-Haemophilus influenzae type b (Hib)-Hepatitis B) vaccine (by card or recall). The proportion of ZD children was calculated and associated factors were explored using logistic regression, taking into account the complex sampling approach. (3) Results: The study included 51,054 children. The proportion of ZD children was 19.1% (95%CI: 19.0–19.2%); ZD ranged from 62.4% in Tshopo to 2.4% in Haut Lomami. After adjustment, being ZD was associated with low level of maternal education and having a young mother/guardian (aged ≤ 19 years); religious affiliation (willful failure to disclose religious affiliation as the highest associated factor compared to being Catholic, followed by Muslims, revival/independent church, Kimbanguist, Protestant); proxies for wealth such as not having a telephone or a radio; having to pay for a vaccination card or for another immunization-related service; not being able to name any vaccine-preventable disease. A child’s lack of civil registration was also associated with being ZD. (4) Conclusions: In 2021, one in five children aged 12–23 months in DRC had never been vaccinated. The factors associated with being a ZD child suggest inequalities in vaccination that must be further explored to better target appropriate interventions. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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12 pages, 615 KiB  
Article
Low Vaccine Coverage and Factors Associated with Incomplete Childhood Immunization in Racial/Ethnic Minorities and Rural Groups, Central Brazil
by Juliana de Oliveira Roque e Lima, Valéria Pagotto, Bárbara Souza Rocha, Paulo Sérgio Scalize, Rafael Alves Guimarães, Márcio Dias de Lima, Leandro Nascimento da Silva, Michele Dias da Silva Oliveira, Winny Éveny Alves Moura, Sheila Araújo Teles, Claci Fátima Weirich Rosso and Karlla Antonieta Amorim Caetano
Vaccines 2023, 11(4), 838; https://doi.org/10.3390/vaccines11040838 - 13 Apr 2023
Cited by 3 | Viewed by 2021
Abstract
Discrimination and limited access to healthcare services in remote areas can affect vaccination coverage. Therefore, this study aimed to estimate vaccination coverage for children living in quilombola communities and rural settlements in the central region of Brazil during their first year of life [...] Read more.
Discrimination and limited access to healthcare services in remote areas can affect vaccination coverage. Therefore, this study aimed to estimate vaccination coverage for children living in quilombola communities and rural settlements in the central region of Brazil during their first year of life and to analyze the factors associated with incomplete vaccination. An analytical cross-sectional study was conducted on children born between 2015 and 2017. The percentage of children who received all vaccines recommended by the National Immunization Program in Brazil by 11 months and 29 days was used to calculate immunization coverage. Children who received the following vaccines were considered as having a complete basic vaccination schedule: one dose of BCG; three doses of Hepatitis B, of Diphtheria-Tetanus-Pertussis (DPT), of Haemophilus influenzae type b (Hib), and of Poliovirus (Polio); two doses of Rotavirus, of 10-valent pneumococcal (PCV10), and of Serogroup C meningococcal conjugate (MenC); and one dose of Yellow Fever (YF). Measles-mumps-rubella (MMR) and other doses recommended at or after 12 months were not included. Consolidated logistic regression was used to identify factors associated with incomplete vaccination coverage. Overall vaccination coverage was 52.8% (95% CI: 45.5–59.9%) and ranged from 70.4% for the Yellow Fever vaccine to 78.3% for the Rotavirus vaccine, with no significant differences between the quilombola and settler groups. Notably, the likelihood of incomplete general vaccination coverage was higher among children who did not receive a visit from a healthcare professional. Urgent strategies are required to achieve and ensure health equity for this unique and traditionally distinct group with low vaccination coverage. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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14 pages, 1240 KiB  
Article
Evaluation of Container Clinics as an Urban Immunization Strategy: Findings from the First Year of Implementation in Ghana, 2017–2018
by Anna Shaum, Melissa T. Wardle, Kwame Amponsa-Achiano, Raymond Aborigo, Joseph Opare, Aaron S. Wallace, Delia Bandoh, Pamela Quaye, Fred Osei-Sarpong, Francis Abotsi, George Bonsu and Laura Conklin
Vaccines 2023, 11(4), 814; https://doi.org/10.3390/vaccines11040814 - 07 Apr 2023
Cited by 2 | Viewed by 1310
Abstract
Background: In 2017, the Expanded Programme on Immunization in Ghana opened two container clinics in Accra, which were cargo containers outfitted to deliver immunizations. At each clinic, we assessed performance and clinic acceptance during the first 12 months of implementation. Methods: We employed [...] Read more.
Background: In 2017, the Expanded Programme on Immunization in Ghana opened two container clinics in Accra, which were cargo containers outfitted to deliver immunizations. At each clinic, we assessed performance and clinic acceptance during the first 12 months of implementation. Methods: We employed a descriptive mixed-method design using monthly administrative immunization data, exit interviews with caregivers of children of <5 years (N = 107), focus group discussions (FGDs) with caregivers (n = 6 FGDs) and nurses (n = 2 FGDs), and in-depth interviews (IDIs) with community leaders (n = 3) and health authorities (n = 3). Results: Monthly administrative data showed that administered vaccine doses increased from 94 during the opening month to 376 in the 12th month across both clinics. Each clinic exceeded its target doses for the 12–23 month population (second dose of measles). Almost all (98%) exit interview participants stated that the clinics made it easier to receive child health services compared to previous health service interactions. The accessibility and acceptability of the container clinics were also supported from health worker and community perspectives. Conclusions: Our initial data support container clinics as an acceptable strategy for delivering immunization services in urban populations, at least in the short term. They can be rapidly deployed and designed to serve working mothers in strategic areas. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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19 pages, 6082 KiB  
Article
Assessing Geographic Overlap between Zero-Dose Diphtheria–Tetanus–Pertussis Vaccination Prevalence and Other Health Indicators
by Emily Haeuser, Jason Q. Nguyen, Sam Rolfe, Olivia Nesbit, Nancy Fullman and Jonathan F. Mosser
Vaccines 2023, 11(4), 802; https://doi.org/10.3390/vaccines11040802 - 05 Apr 2023
Cited by 1 | Viewed by 2081
Abstract
The integration of immunization with other essential health services is among the strategic priorities of the Immunization Agenda 2030 and has the potential to improve the effectiveness, efficiency, and equity of health service delivery. This study aims to evaluate the degree of spatial [...] Read more.
The integration of immunization with other essential health services is among the strategic priorities of the Immunization Agenda 2030 and has the potential to improve the effectiveness, efficiency, and equity of health service delivery. This study aims to evaluate the degree of spatial overlap between the prevalence of children who have never received a dose of the diphtheria–tetanus–pertussis-containing vaccine (no-DTP) and other health-related indicators, to provide insight into the potential for joint geographic targeting of integrated service delivery efforts. Using geospatially modeled estimates of vaccine coverage and comparator indicators, we develop a framework to delineate and compare areas of high overlap across indicators, both within and between countries, and based upon both counts and prevalence. We derive summary metrics of spatial overlap to facilitate comparison between countries and indicators and over time. As an example, we apply this suite of analyses to five countries—Nigeria, Democratic Republic of the Congo (DRC), Indonesia, Ethiopia, and Angola—and five comparator indicators—children with stunting, under-5 mortality, children missing doses of oral rehydration therapy, prevalence of lymphatic filariasis, and insecticide-treated bed net coverage. Our results demonstrate substantial heterogeneity in the geographic overlap both within and between countries. These results provide a framework to assess the potential for joint geographic targeting of interventions, supporting efforts to ensure that all people, regardless of location, can benefit from vaccines and other essential health services. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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17 pages, 2147 KiB  
Article
Inequalities in Immunization against Maternal and Neonatal Tetanus: A Cross-Sectional Analysis of Protection at Birth Coverage Using Household Health Survey Data from 76 Countries
by Nicole E. Johns, Bianca O. Cata-Preta, Katherine Kirkby, Luisa Arroyave, Nicole Bergen, M. Carolina Danovaro-Holliday, Thiago M. Santos, Nasir Yusuf, Aluísio J. D. Barros and Ahmad Reza Hosseinpoor
Vaccines 2023, 11(4), 752; https://doi.org/10.3390/vaccines11040752 - 29 Mar 2023
Cited by 2 | Viewed by 2104
Abstract
Substantial progress in maternal and neonatal tetanus elimination has been made in the past 40 years, with dramatic reductions in neonatal tetanus incidence and mortality. However, twelve countries have still not achieved maternal and neonatal tetanus elimination, and many countries that have achieved [...] Read more.
Substantial progress in maternal and neonatal tetanus elimination has been made in the past 40 years, with dramatic reductions in neonatal tetanus incidence and mortality. However, twelve countries have still not achieved maternal and neonatal tetanus elimination, and many countries that have achieved elimination do not meet key sustainability thresholds to ensure long-lasting elimination. As maternal and neonatal tetanus is a vaccine-preventable disease (with coverage of the infant conferred by maternal immunization during and prior to pregnancy), maternal tetanus immunization coverage is a key metric for monitoring progress towards, equity in, and sustainability of tetanus elimination. In this study, we examine inequalities in tetanus protection at birth, a measure of maternal immunization coverage, across 76 countries and four dimensions of inequality via disaggregated data and summary measures of inequality. We find that substantial inequalities in coverage exist for wealth (with lower coverage among poorer wealth quintiles), maternal age (with lower coverage among younger mothers), maternal education (with lower coverage among less educated mothers), and place of residence (with lower coverage in rural areas). Inequalities existed for all dimensions across low- and lower-middle-income countries, and across maternal education and place of residence across upper-middle-income countries. Though global coverage changed little over the time period 2001–2020, this obscured substantial heterogeneity across countries. Notably, several countries had substantial increases in coverage accompanied by decreases in inequality, highlighting the need for equity considerations in maternal and neonatal tetanus elimination and sustainability efforts. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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17 pages, 1373 KiB  
Article
Sociodemographic Factors Associated with COVID-19 Vaccination among People in Guatemalan Municipalities
by Rewa Choudhary, Emily Carter, Jose Monzon, Allison Stewart, Jennifer Slotnick, Leslie L. Samayoa Jerez, David S. Rodriguez Araujo, Emily Zielinski-Gutierrez and Parminder S. Suchdev
Vaccines 2023, 11(4), 745; https://doi.org/10.3390/vaccines11040745 - 28 Mar 2023
Cited by 2 | Viewed by 2213
Abstract
The Republic of Guatemala’s reported COVID-19 vaccination coverage is among the lowest in the Americas and there are limited studies describing the disparities in vaccine uptake within the country. We performed a cross-sectional ecological analysis using multi-level modeling to identify sociodemographic characteristics that [...] Read more.
The Republic of Guatemala’s reported COVID-19 vaccination coverage is among the lowest in the Americas and there are limited studies describing the disparities in vaccine uptake within the country. We performed a cross-sectional ecological analysis using multi-level modeling to identify sociodemographic characteristics that were associated with low COVID-19 vaccination coverage among Guatemalan municipalities as of 30 November 2022. Municipalities with a higher proportion of people experiencing poverty (β = −0.25, 95% CI: −0.43–−0.07) had lower vaccination coverage. Municipalities with a higher proportion of people who had received at least a primary education (β = 0.74, 95% CI: 0.38–1.08), children (β = 1.07, 95% CI: 0.36–1.77), people aged 60 years and older (β = 2.94, 95% CI: 1.70–4.12), and testing for SARS-CoV-2 infection (β = 0.25, 95% CI: 0.14–0.36) had higher vaccination coverage. In the simplified multivariable model, these factors explained 59.4% of the variation in COVID-19 vaccination coverage. Poverty remained significantly associated with low COVID-19 vaccination coverage in two subanalyses restricting the data to the time period of the highest national COVID-19-related death rate and to COVID-19 vaccination coverage only among those aged 60 years or older. Poverty is a key factor associated with low COVID-19 vaccination and focusing public health interventions in municipalities most affected by poverty may help address COVID-19 vaccination and health disparities in Guatemala. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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15 pages, 561 KiB  
Article
Uncovering the Drivers of Childhood Immunization Inequality with Caregivers, Community Members and Health System Stakeholders: Results from a Human-Centered Design Study in DRC, Mozambique and Nigeria
by Jessica C. Shearer, Olivia Nava, Wendy Prosser, Saira Nawaz, Salva Mulongo, Thérèse Mambu, Eric Mafuta, Khatia Munguambe, Betuel Sigauque, Yakubu Joel Cherima, Olawale Durosinmi-Etti, Obehi Okojie, Idris Suleman Hadejia, Femi Oyewole, Dessie Ayalew Mekonnen, Natasha Kanagat, Carol Hooks, Rebecca Fields, Vanessa Richart and Grace Chee
Vaccines 2023, 11(3), 689; https://doi.org/10.3390/vaccines11030689 - 17 Mar 2023
Cited by 5 | Viewed by 5746
Abstract
Background: The importance of immunization for child survival underscores the need to eliminate immunization inequalities. Few existing studies of inequalities use approaches that view the challenges and potential solutions from the perspective of caregivers. This study aimed to identify barriers and context-appropriate solutions [...] Read more.
Background: The importance of immunization for child survival underscores the need to eliminate immunization inequalities. Few existing studies of inequalities use approaches that view the challenges and potential solutions from the perspective of caregivers. This study aimed to identify barriers and context-appropriate solutions by engaging deeply with caregivers, community members, health workers, and other health system actors through participatory action research, intersectionality, and human-centered design lenses. Methods: This study was conducted in the Demographic Republic of Congo, Mozambique and Nigeria. Rapid qualitative research was followed by co-creation workshops with study participants to identify solutions. We analyzed the data using the UNICEF Journey to Health and Immunization Framework. Results: Caregivers of zero-dose and under-immunized children faced multiple intersecting and interacting barriers related to gender, poverty, geographic access, and service experience. Immunization programs were not aligned with needs of the most vulnerable due to the sub-optimal implementation of pro-equity strategies, such as outreach vaccination. Caregivers and communities identified feasible solutions through co-creation workshops and this approach should be used whenever possible to inform local planning. Conclusions: Policymakers and managers can integrate HCD and intersectionality mindsets into existing planning and assessment processes, and focus on overcoming root causes of sub-optimal implementation. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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15 pages, 8818 KiB  
Article
Immunization Gender Inequity in Pakistan: An Analysis of 6.2 Million Children Born from 2019 to 2022 and Enrolled in the Sindh Electronic Immunization Registry
by Danya Arif Siddiqi, Sundus Iftikhar, Muhammad Siddique, Mariam Mehmood, Vijay Kumar Dharma, Mubarak Taighoon Shah, Hamidreza Setayesh and Subhash Chandir
Vaccines 2023, 11(3), 685; https://doi.org/10.3390/vaccines11030685 - 17 Mar 2023
Cited by 1 | Viewed by 2128
Abstract
Gender-based inequities in immunization impede the universal coverage of childhood vaccines. Leveraging data from the Government of Sindh’s Electronic Immunization Registry (SEIR), we estimated inequalities in immunization for males and females from the 2019–2022 birth cohorts in Pakistan. We computed male-to-female (M:F) and [...] Read more.
Gender-based inequities in immunization impede the universal coverage of childhood vaccines. Leveraging data from the Government of Sindh’s Electronic Immunization Registry (SEIR), we estimated inequalities in immunization for males and females from the 2019–2022 birth cohorts in Pakistan. We computed male-to-female (M:F) and gender inequality ratios (GIR) Tfor enrollment, vaccine coverage, and timeliness. We also explored the inequities by maternal literacy, geographic location, mode of vaccination delivery, and gender of vaccinators. Between 1 January 2019, and 31 December 2022, 6,235,305 children were enrolled in the SEIR, 52.2% males and 47.8% females. We observed a median M:F ratio of 1.03 at enrollment and at Penta-1, Penta-3, and Measles-1 vaccinations, indicating more males were enrolled in the immunization system than females. Once enrolled, a median GIR of 1.00 indicated similar coverage for females and males over time; however, females experienced a delay in their vaccination timeliness. Low maternal education; residing in remote-rural, rural, and slum regions; and receiving vaccines at fixed sites, as compared to outreach, were associated with fewer females being vaccinated, as compared to males. Our findings suggeste the need to tailor and implement gender-sensitive policies and strategies for improving equity in immunization, especially in vulnerable geographies with persistently high inequalities. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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13 pages, 528 KiB  
Article
Determinants of Equity in Coverage of Measles-Containing Vaccines in Wales, UK, during the Elimination Era
by Malorie Perry, Simon Cottrell, Michael B. Gravenor and Lucy Griffiths
Vaccines 2023, 11(3), 680; https://doi.org/10.3390/vaccines11030680 - 17 Mar 2023
Cited by 3 | Viewed by 2313
Abstract
In the context of the WHO’s measles and rubella elimination targets and European Immunization Agenda 2030, this large cross-sectional study aimed to identify inequalities in measles vaccination coverage in Wales, UK. The vaccination status of individuals aged 2 to 25 years of age, [...] Read more.
In the context of the WHO’s measles and rubella elimination targets and European Immunization Agenda 2030, this large cross-sectional study aimed to identify inequalities in measles vaccination coverage in Wales, UK. The vaccination status of individuals aged 2 to 25 years of age, alive and resident in Wales as of 31 August 2021, was ascertained through linkage of the National Community Child Health Database and primary care data. A series of predictor variables were derived from five national datasets and all analysis was carried out in the Secure Anonymised Information Linkage Databank at Swansea University. In these 648,895 individuals, coverage of the first dose of measles-containing vaccine (due at 12–13 months of age) was 97.1%, and coverage of the second dose (due at 3 years and 4 months) in 4 to 25-year-olds was 93.8%. In multivariable analysis, excluding 0.7% with known refusal, the strongest association with being unvaccinated was birth order (families with six or more children) and being born outside of the UK. Living in a deprived area, being eligible for free school meals, a lower level of maternal education, and having a recorded language other than English or Welsh were also associated with lower coverage. Some of these factors may also be associated with refusal. This knowledge can be used to target future interventions and prioritise areas for catch up in a time of limited resource. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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14 pages, 3267 KiB  
Article
Tetanus and Diphtheria Seroprotection among Children Younger Than 15 Years in Nigeria, 2018: Who Are the Unprotected Children?
by Rania A. Tohme, Heather M. Scobie, Oyeladun Okunromade, Temitope Olaleye, Faisal Shuaib, Tunde Jegede, Ridwan Yahaya, Ndodo Nnaemeka, Bola Lawal, Abiodun Egwuenu, Nishanth Parameswaran, Gretchen Cooley, Qian An, Melissa Coughlin, Bassey B. Okposen, Ifedayo Adetifa, Omotayo Bolu and Chikwe Ihekweazu
Vaccines 2023, 11(3), 663; https://doi.org/10.3390/vaccines11030663 - 15 Mar 2023
Cited by 4 | Viewed by 2735
Abstract
Serological surveys provide an objective biological measure of population immunity, and tetanus serological surveys can also assess vaccination coverage. We undertook a national assessment of immunity to tetanus and diphtheria among Nigerian children aged <15 years using stored specimens collected during the 2018 [...] Read more.
Serological surveys provide an objective biological measure of population immunity, and tetanus serological surveys can also assess vaccination coverage. We undertook a national assessment of immunity to tetanus and diphtheria among Nigerian children aged <15 years using stored specimens collected during the 2018 Nigeria HIV/AIDS Indicator and Impact Survey, a national cross-sectional household-based survey. We used a validated multiplex bead assay to test for tetanus and diphtheria toxoid-antibodies. In total, 31,456 specimens were tested. Overall, 70.9% and 84.3% of children aged <15 years had at least minimal seroprotection (≥0.01 IU/mL) against tetanus and diphtheria, respectively. Seroprotection was lowest in the north west and north east zones. Factors associated with increased tetanus seroprotection included living in the southern geopolitical zones, urban residence, and higher wealth quintiles (p < 0.001). Full seroprotection (≥0.1 IU/mL) was the same for tetanus (42.2%) and diphtheria (41.7%), while long-term seroprotection (≥1 IU/mL) was 15.1% for tetanus and 6.0% for diphtheria. Full- and long-term seroprotection were higher in boys compared to girls (p < 0.001). Achieving high infant vaccination coverage by targeting specific geographic areas and socio-economic groups and introducing tetanus and diphtheria booster doses in childhood and adolescence are needed to achieve lifelong protection against tetanus and diphtheria and prevent maternal and neonatal tetanus. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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19 pages, 13303 KiB  
Article
Assessing Potential Exemplars in Reducing Zero-Dose Children: A Novel Approach for Identifying Positive Outliers in Decreasing National Levels and Geographic Inequalities in Unvaccinated Children
by Nancy Fullman, Gustavo C. Correa, Gloria Ikilezi, David E. Phillips and Heidi W. Reynolds
Vaccines 2023, 11(3), 647; https://doi.org/10.3390/vaccines11030647 - 14 Mar 2023
Cited by 1 | Viewed by 2288
Abstract
Background: Understanding past successes in reaching unvaccinated or “zero-dose” children can help inform strategies for improving childhood immunization in other settings. Drawing from positive outlier methods, we developed a novel approach for identifying potential exemplars in reducing zero-dose children. Methods: Focusing on 2000–2019, [...] Read more.
Background: Understanding past successes in reaching unvaccinated or “zero-dose” children can help inform strategies for improving childhood immunization in other settings. Drawing from positive outlier methods, we developed a novel approach for identifying potential exemplars in reducing zero-dose children. Methods: Focusing on 2000–2019, we assessed changes in the percentage of under-one children with no doses of the diphtheria–tetanus–pertussis vaccine (no-DTP) across two geographic dimensions in 56 low- or lower-middle-income countries: (1) national levels; (2) subnational gaps, as defined as the difference between the 5th and 95th percentiles of no-DTP prevalence across second administrative units. Countries with the largest reductions for both metrics were considered positive outliers or potential ‘exemplars’, demonstrating exception progress in reducing national no-DTP prevalence and subnational inequalities. Last, so-called “neighborhood analyses” were conducted for the Gavi Learning Hub countries (Nigeria, Mali, Uganda, and Bangladesh), comparing them with countries that had similar no-DTP measures in 2000 but different trajectories through 2019. Results: From 2000 to 2019, the Democratic Republic of the Congo, Ethiopia, and India had the largest absolute decreases for the two no-DTP dimensions—national prevalence and subnational gaps—while Bangladesh and Burundi registered the largest relative reductions for each no-DTP metric. Neighborhood analyses highlighted possible opportunities for cross-country learning among Gavi Learning Hub countries and potential exemplars in reducing zero-dose children. Conclusions: Identifying where exceptional progress has occurred is the first step toward better understanding how such gains could be achieved elsewhere. Further examination of how countries have successfully reduced levels of zero-dose children—especially across variable contexts and different drivers of inequality—could support faster, sustainable advances toward greater vaccination equity worldwide. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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10 pages, 538 KiB  
Article
The Hidden Impact of the COVID-19 Pandemic on Routine Childhood Immunization Coverage in Cameroon
by Yauba Saidu, Pietro Di Mattei, Sangwe Clovis Nchinjoh, Nnang Nadege Edwige, Bernard Nsah, Nkwain Jude Muteh, Shalom Tchokfe Ndoula, Rakiya Abdullahi, Chen Stein Zamir, Andreas Ateke Njoh, Amani Adidja, Sidy Ndiaye, Owens Wiwa, Emanuele Montomoli and Sue Ann Costa Clemens
Vaccines 2023, 11(3), 645; https://doi.org/10.3390/vaccines11030645 - 14 Mar 2023
Cited by 4 | Viewed by 2694
Abstract
Background: The third round of the global pulse survey demonstrated that the abrupt and rapid progression of the COVID-19 pandemic significantly disrupted childhood immunization in many countries. Although Cameroon has reported over 120,000 COVID-19 cases, the reported national childhood vaccination coverage during [...] Read more.
Background: The third round of the global pulse survey demonstrated that the abrupt and rapid progression of the COVID-19 pandemic significantly disrupted childhood immunization in many countries. Although Cameroon has reported over 120,000 COVID-19 cases, the reported national childhood vaccination coverage during the pandemic seems to have increased compared to that during the pre-COVID-19 period. Indeed, the first dose of the diphtheria, tetanus, and pertussis-containing vaccine (DTP-1) coverage increased from 85.4% in 2019 to 87.7% in 2020, and DTP-3 coverage increased from 79.5% in 2019 to 81.2% in 2020. The paucity of literature on the impact of COVID-19 on childhood vaccination in COVID-19 hotspot regions poses a challenge in developing a context-specific immunization recovery plan, hence the need to conduct this study. Methodology: We conducted a cross-sectional study using 2019 (pre-pandemic period) and 2020 (pandemic period) district childhood immunization data from the DHIS-2 database, weighted using completeness for each data entry against regional data completeness in 2020. Based on COVID-19 incidence, two hotspot regions were selected, with all districts (56/56) included in the final analysis. The Chi-square test was used to compare DTP-1 and DTP-3 coverage during the pre-pandemic and pandemic periods. Results: In the two hotspot regions, 8247 children missed DTP-1, and 12,896 children did not receive DTP-3 vaccines in the pandemic period compared to the results from the pre-pandemic period. Indeed, there was a significant drop in DTP-1 and DTP-3 coverage of 0.8% (p = 0.0002) and 3.1% (p = 0.0003), respectively, in the Littoral Region. Moreover, the Centre Region reported a 5.7% (p < 0.0001) and 7.6% (p < 0.0001) drop in DTP-1 and DTP-3 coverage, respectively. Most districts in the hotspot regions reported a decline in childhood immunization access (62.5%) and utilization (71.4%). Indeed, in the Littoral Region, 46% (11/24) and 58% (14/24) of districts experienced decreased vaccination access and utilization, respectively. Meanwhile, 75% (24/32) and 81% (26/32) of districts in the Centre Region experienced a drop in vaccination access and utilization, respectively. Conclusion: This study reported a situation where the national immunization indicators mask the impact of COVID-19 on childhood immunization in heavily hit regions. Therefore, this study presents valuable information for ensuring continuous vaccination service delivery during public health emergencies. The findings could also contribute to developing an immunization recovery plan and informing policy on future pandemic preparedness and response. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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13 pages, 1728 KiB  
Article
Challenges Addressing Inequalities in Measles Vaccine Coverage in Zambia through a Measles–Rubella Supplementary Immunization Activity during the COVID-19 Pandemic
by Yangyupei Yang, Natalya Kostandova, Francis Dien Mwansa, Chola Nakazwe, Harriet Namukoko, Constance Sakala, Patricia Bobo, Penelope Kalesha Masumbu, Bertha Nachinga, David Ngula, Andrea C. Carcelen, Christine Prosperi, Amy K. Winter, William J. Moss and Simon Mutembo
Vaccines 2023, 11(3), 608; https://doi.org/10.3390/vaccines11030608 - 07 Mar 2023
Cited by 1 | Viewed by 2149
Abstract
Background: Measles–rubella supplementary immunization activities (MR-SIAs) are conducted to address inequalities in coverage and fill population immunity gaps when routine immunization services fail to reach all children with two doses of a measles-containing vaccine (MCV). We used data from a post-campaign coverage survey [...] Read more.
Background: Measles–rubella supplementary immunization activities (MR-SIAs) are conducted to address inequalities in coverage and fill population immunity gaps when routine immunization services fail to reach all children with two doses of a measles-containing vaccine (MCV). We used data from a post-campaign coverage survey in Zambia to measure the proportion of measles zero-dose and under-immunized children who were reached by the 2020 MR-SIA and identified reasons associated with persistent inequalities following the MR-SIA. Methods: Children between 9 and 59 months were enrolled in a nationally representative, cross-sectional, multistage stratified cluster survey in October 2021 to estimate vaccination coverage during the November 2020 MR-SIA. Vaccination status was determined by immunization card or through caregivers’ recall. MR-SIA coverage and the proportion of measles zero-dose and under-immunized children reached by MR-SIA were estimated. Log-binomial models were used to assess risk factors for missing the MR-SIA dose. Results: Overall, 4640 children were enrolled in the nationwide coverage survey. Only 68.6% (95% CI: 66.7%, 70.6%) received MCV during the MR-SIA. The MR-SIA provided MCV1 to 4.2% (95% CI: 0.9%, 4.6%) and MCV2 to 6.3% (95% CI: 5.6%, 7.1%) of enrolled children, but 58.1% (95% CI: 59.8%, 62.8%) of children receiving the MR-SIA dose had received at least two prior MCV doses. Furthermore, 27.8% of measles zero-dose children were vaccinated through the MR-SIA. The MR-SIA reduced the proportion of measles zero-dose children from 15.1% (95% CI: 13.6%, 16.7%) to 10.9% (95% CI: 9.7%, 12.3%). Zero-dose and under-immunized children were more likely to miss MR-SIA doses (prevalence ratio (PR): 2.81; 95% CI: 1.80, 4.41 and 2.22; 95% CI: 1.21 and 4.07) compared to fully vaccinated children. Conclusions: The MR-SIA reached more under-immunized children with MCV2 than measles zero-dose children with MCV1. However, improvement is needed to reach the remaining measles zero-dose children after SIA. One possible solution to address the inequalities in vaccination is to transition from nationwide non-selective SIAs to more targeted and selective strategies. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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14 pages, 254 KiB  
Article
Comparing Multivariate with Wealth-Based Inequity in Vaccination Coverage in 56 Countries: Toward a Better Measure of Equity in Vaccination Coverage
by Bryan N. Patenaude, Salin Sriudomporn, Deborah Odihi, Joshua Mak and Gatien de Broucker
Vaccines 2023, 11(3), 536; https://doi.org/10.3390/vaccines11030536 - 24 Feb 2023
Cited by 1 | Viewed by 1422
Abstract
Introduction: Following a call from the World Health Organization in 2017 for a methodology to monitor immunization coverage equity in line with the 2030 Agenda for Sustainable Development, this study applies the Vaccine Economics Research for Sustainability and Equity (VERSE) vaccination equity toolkit [...] Read more.
Introduction: Following a call from the World Health Organization in 2017 for a methodology to monitor immunization coverage equity in line with the 2030 Agenda for Sustainable Development, this study applies the Vaccine Economics Research for Sustainability and Equity (VERSE) vaccination equity toolkit to measure national-level inequity in immunization coverage using a multidimensional ranking procedure and compares this with traditional wealth-quintile based ranking methods for assessing inequity. The analysis covers 56 countries with a most recent Demographic & Health Survey (DHS) between 2010 and 2022. The vaccines examined include Bacillus Calmette–Guerin (BCG), Diphtheria–Tetanus–Pertussis-containing vaccine doses 1 through 3 (DTP1–3), polio vaccine doses 1–3 (Polio1–3), the measles-containing vaccine first dose (MCV1), and an indicator for being fully immunized for age with each of these vaccines. Materials & Methods: The VERSE equity toolkit is applied to 56 DHS surveys to rank individuals by multiple disadvantages in vaccination coverage, incorporating place of residence (urban/rural), geographic region, maternal education, household wealth, sex of the child, and health insurance coverage. This rank is used to estimate a concentration index and absolute equity coverage gap (AEG) between the top and bottom quintiles, ranked by multiple disadvantages. The multivariate concentration index and AEG are then compared with traditional concentration index and AEG measures, which use household wealth as the sole criterion for ranking individuals and determining quintiles. Results: We find significant differences between the two sets of measures in almost all settings. For fully-immunized for age status, the inequities captured using the multivariate metric are between 32% and 324% larger than what would be captured examining inequities using traditional metrics. This results in a missed coverage gap of between 1.1 and 46.4 percentage points between the most and least advantaged. Conclusions: The VERSE equity toolkit demonstrated that wealth-based inequity measures systematically underestimate the gap between the most and least advantaged in fully-immunized for age coverage, correlated with maternal education, geography, and sex by 1.1–46.4 percentage points, globally. Closing the coverage gap between the bottom and top wealth quintiles is unlikely to eliminate persistent socio-demographic inequities in either coverage or access to vaccines. The results suggest that pro-poor interventions and programs utilizing needs-based targeting, which reflects poverty only, should expand their targeting criteria to include other dimensions to reduce systemic inequalities, holistically. Additionally, a multivariate metric should be considered when setting targets and measuring progress toward reducing inequities in healthcare coverage. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
13 pages, 3092 KiB  
Article
Mapping of Pro-Equity Interventions Proposed by Immunisation Programs in Gavi Health Systems Strengthening Grants
by Joelle Ducharme, Gustavo Caetano Correa, Heidi W. Reynolds, Alyssa B. Sharkey, Virginia A. Fonner and Mira Johri
Vaccines 2023, 11(2), 341; https://doi.org/10.3390/vaccines11020341 - 02 Feb 2023
Cited by 1 | Viewed by 2645
Abstract
Reaching zero-dose (ZD) children, operationally defined as children who have not received a first dose of the diphtheria, tetanus, and pertussis (DTP1) vaccine, is crucial to increase equitable immunisation coverage and access to primary health care. However, little is known about the approaches [...] Read more.
Reaching zero-dose (ZD) children, operationally defined as children who have not received a first dose of the diphtheria, tetanus, and pertussis (DTP1) vaccine, is crucial to increase equitable immunisation coverage and access to primary health care. However, little is known about the approaches already taken by countries to improve immunisation equity. We reviewed all Health System Strengthening (HSS) proposals submitted by Gavi-supported countries from 2014 to 2021 inclusively and extracted information on interventions favouring equity. Pro-equity interventions were mapped to an analytical framework representing Gavi 5.0 programmatic guidance on reaching ZD children and missed communities. Data from keyword searches and manual screening were extracted into an Excel database. Open format responses were analysed using inductive and deductive thematic coding. Data analysis was conducted using Excel and R. Of the 56 proposals included, 51 (91%) included at least one pro-equity intervention. The most common interventions were conducting outreach sessions, tailoring the location of service delivery, and partnerships. Many proposals had “bundles” of interventions, most often involving outreach, microplanning and community-level education activities. Nearly half prioritised remote-rural areas and only 30% addressed gender-related barriers to immunisation. The findings can help identify specific interventions on which to focus future evidence syntheses, case studies and implementation research and inform discussions on what may or may not need to change to better reach ZD children and missed communities moving forward. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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14 pages, 1410 KiB  
Article
Advancing Immunization Coverage and Equity: A Structured Synthesis of Pro-Equity Strategies in 61 Gavi-Supported Countries
by Vesela Ivanova, A. S. M. Shahabuddin, Alyssa Sharkey and Mira Johri
Vaccines 2023, 11(1), 191; https://doi.org/10.3390/vaccines11010191 - 16 Jan 2023
Cited by 3 | Viewed by 2634
Abstract
Background: Global immunization inequities persist, reflected in the 25 million underimmunized and 18 million zero-dose children in 2021. To identify country approaches to reach underimmunized and zero-dose children, we undertook a structured synthesis of pro-equity strategies across 61 countries receiving programmatic support from [...] Read more.
Background: Global immunization inequities persist, reflected in the 25 million underimmunized and 18 million zero-dose children in 2021. To identify country approaches to reach underimmunized and zero-dose children, we undertook a structured synthesis of pro-equity strategies across 61 countries receiving programmatic support from Gavi, the Vaccine Alliance. Methods: We extracted data from 174 Country Joint Appraisals and Multi-Stakeholder Dialogue reports (2016–2020). We identified strategies via a targeted keyword search, informed by a determinants of immunization coverage framework. Strategies were synthesized into themes consolidated from UNICEF’s Journey to Health and Immunization (JTHI) and the Global Routine Immunization Strategies and Practices (GRISP) frameworks. Results: We found 607 unique strategies across 61 countries and 24 themes. Strategies to improve care at the point of service (44%); to improve knowledge, awareness and beliefs (25%); and to address preparation, cost and effort barriers (13%) were common. Fewer strategies targeted experience of care (8%), intent, (7%) and after-service (3%). We also identified strategies addressing gender-related barriers to immunization and targeting specific types of communities. Conclusions: We summarize the range of pro-equity immunization strategies employed in Gavi-supported countries and interpret them thematically. Findings are incorporated into a searchable database which can be used to inform equity-driven immunization programs, policies and decision-making which target underimmunized and zero-dose communities. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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9 pages, 239 KiB  
Article
Disparities in Coverage of Adult Immunization among Older Adults in India
by Damini Singh, Abhinav Sinha, Srikanta Kanungo and Sanghamitra Pati
Vaccines 2022, 10(12), 2124; https://doi.org/10.3390/vaccines10122124 - 12 Dec 2022
Cited by 3 | Viewed by 1724
Abstract
A lack of a universal adult immunization scheme in India poses a challenge to achieve universal health coverage. Healthcare disparity is one of the biggest challenges in low- and middle-income countries such as India. We aimed to estimate the disparities in coverage of [...] Read more.
A lack of a universal adult immunization scheme in India poses a challenge to achieve universal health coverage. Healthcare disparity is one of the biggest challenges in low- and middle-income countries such as India. We aimed to estimate the disparities in coverage of various adult vaccines among older adults in India using nationally representative data. An observational analysis among 31,464 participants aged ≥60 years from the Longitudinal Ageing Study in India, 2017–2018, was conducted. Vaccination coverage across wealth quintiles and selected non-communicable diseases were reported as frequencies and weighted proportions along with their 95% confidence intervals as a measure of uncertainty. The highest coverage was of the diphtheria and tetanus vaccine (2.75%) followed by typhoid (1.84%), hepatitis B (1.82%), influenza (1.59%), and pneumococcal (0.74%). The most affluent groups had a higher coverage of all vaccines. Participants having high cholesterol, psychiatric conditions, and cancer had the highest coverage of all vaccines. Overall, a very low coverage of all vaccines was observed. The coverage was influenced by social determinants of health, depicting a disparity in accessing immunization. Hence, at-risk groups such as the deprived and multimorbid patients need to be covered under the ambit of free immunization to achieve universal health coverage. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
11 pages, 266 KiB  
Article
Factors Associated with Zero-Dose Childhood Vaccination Status in a Remote Fishing Community in Cameroon: A Cross-Sectional Analytical Study
by Sangwe Clovis Nchinjoh, Yauba Saidu, Valirie Ndip Agbor, Clarence Mvalo Mbanga, Nkwain Jude Muteh, Andreas Ateke Njoh, Shalom Tchofke Ndoula, Bernard Nsah, Nnang Nadege Edwige, Sveta Roberman and Chen Stein Zamir
Vaccines 2022, 10(12), 2052; https://doi.org/10.3390/vaccines10122052 - 30 Nov 2022
Cited by 2 | Viewed by 3009
Abstract
Background: Cameroon’s suboptimal access to childhood vaccinations poses a significant challenge to achieving the Immunization Agenda 2030 goal—ranking among the top 15 countries with a high proportion of zero-dose (unvaccinated) children worldwide. There are clusters of zero-dose children in pockets of communities [...] Read more.
Background: Cameroon’s suboptimal access to childhood vaccinations poses a significant challenge to achieving the Immunization Agenda 2030 goal—ranking among the top 15 countries with a high proportion of zero-dose (unvaccinated) children worldwide. There are clusters of zero-dose children in pockets of communities that traditionally miss essential healthcare services, including vaccination. The Manoka Health District (MHD) is home to such settlements with consistently low vaccination coverages (DPT-HepB-Hib-1: 19.8% in 2021) and frequent outbreaks of vaccine-preventable diseases (VPD). Therefore, the absence of literature on zero-dose children in this context was a clarion call to characterize zero-dose children in fragile settings to inform policy and intervention design. Methodology: This cross-sectional analytical study involved 278 children, 0–24 months of age, selected from a 2020 door-to-door survey conducted in the two most populous health areas in an archipelago rural district, MHD (Cap-Cameroon and Toube). We used R Statistical Software (v4.1.2; R Core Team 2021) to run a multivariable logistic regression to determine zero-dose associated factors. Results: The survey revealed a zero-dose proportion of 91.7% (255) in MHD. Children who were delivered in health facilities were less likely to be zero-dose than those born at home (AOR: 0.07, 95% CI: 0.02–0.30, p = 0.0003). Compared to children born of Christian mothers, children born to minority non-Christian mothers had higher odds of being zero-dose (AOR: 6.55, 95% CI: 1.04–41.25, p = 0.0453). Children born to fathers who are immigrants were more likely to be zero-dose children than Cameroonians (AOR: 2.60, 95% CI = 0.65–10.35, p = 0.0016). Younger children were likely to be unvaccinated compared to older peers (AOR: 0.90, 95% CI: 0.82–1.00, p = 0.0401). Conclusions: In the spirit of “leaving no child behind,” the study highlights the need to develop context-specific approaches that consider minority religious groups, immigrants, and younger children, including newborns, often missed during vaccination campaigns and outreaches Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
11 pages, 1824 KiB  
Article
Subnational Gender Inequality and Childhood Immunization: An Ecological Analysis of the Subnational Gender Development Index and DTP Coverage Outcomes across 57 Countries
by Nicole E. Johns, Katherine Kirkby, Tracey S. Goodman, Shirin Heidari, Jean Munro, Stephanie Shendale and Ahmad Reza Hosseinpoor
Vaccines 2022, 10(11), 1951; https://doi.org/10.3390/vaccines10111951 - 18 Nov 2022
Cited by 3 | Viewed by 2144
Abstract
The role of gender inequality in childhood immunization is an emerging area of focus for global efforts to improve immunization coverage and equity. Recent studies have examined the relationship between gender inequality and childhood immunization at national as well as individual levels; we [...] Read more.
The role of gender inequality in childhood immunization is an emerging area of focus for global efforts to improve immunization coverage and equity. Recent studies have examined the relationship between gender inequality and childhood immunization at national as well as individual levels; we hypothesize that the demonstrated relationship between greater gender equality and higher immunization coverage will also be evident when examining subnational-level data. We thus conducted an ecological analysis examining the association between the Subnational Gender Development Index (SGDI) and two measures of immunization—zero-dose diphtheria-tetanus-pertussis (DTP) prevalence and 3-dose DTP coverage. Using data from 2010–2019 across 702 subnational regions within 57 countries, we assessed these relationships using fractional logistic regression models, as well as a series of analyses to account for the nested geographies of subnational regions within countries. Subnational regions were dichotomized to higher gender inequality (top quintile of SGDI) and lower gender inequality (lower four quintiles of SGDI). In adjusted models, we find that subnational regions with higher gender inequality (favoring men) are expected to have 5.8 percentage points greater zero-dose prevalence than regions with lower inequality [16.4% (95% confidence interval (CI) 14.5–18.4%) in higher-inequality regions versus 10.6% (95% CI 9.5–11.7%) in lower-inequality regions], and 8.2 percentage points lower DTP3 immunization coverage [71.0% (95% CI 68.3–73.7%) in higher-inequality regions versus 79.2% (95% CI 77.7–80.7%) in lower-inequality regions]. In models accounting for country-level clustering of gender inequality, the magnitude and strength of associations are reduced somewhat, but remain statistically significant in the hypothesized direction. In conjunction with published work demonstrating meaningful associations between greater gender equality and better childhood immunization outcomes in individual- and country-level analyses, these findings lend further strength to calls for efforts towards greater gender equality to improve childhood immunization and child health outcomes broadly. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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Review

Jump to: Editorial, Research, Other

16 pages, 602 KiB  
Review
Achieving the IA2030 Coverage and Equity Goals through a Renewed Focus on Urban Immunization
by Ibrahim Dadari, Rachel V. Belt, Ananya Iyengar, Arindam Ray, Iqbal Hossain, Daniel Ali, Niklas Danielsson, Samir V. Sodha and The Global Urban Immunization Working Group
Vaccines 2023, 11(4), 809; https://doi.org/10.3390/vaccines11040809 - 06 Apr 2023
Cited by 3 | Viewed by 3147
Abstract
The 2021 WHO and UNICEF Estimates of National Immunization Coverage (WUENIC) reported approximately 25 million under-vaccinated children in 2021, out of which 18 million were zero-dose children who did not receive even the first dose of a diphtheria-tetanus-pertussis-(DPT) containing vaccine. The number of [...] Read more.
The 2021 WHO and UNICEF Estimates of National Immunization Coverage (WUENIC) reported approximately 25 million under-vaccinated children in 2021, out of which 18 million were zero-dose children who did not receive even the first dose of a diphtheria-tetanus-pertussis-(DPT) containing vaccine. The number of zero-dose children increased by six million between 2019, the pre-pandemic year, and 2021. A total of 20 countries with the highest number of zero-dose children and home to over 75% of these children in 2021 were prioritized for this review. Several of these countries have substantial urbanization with accompanying challenges. This review paper summarizes routine immunization backsliding following the COVID-19 pandemic and predictors of coverage and identifies pro-equity strategies in urban and peri-urban settings through a systematic search of the published literature. Two databases, PubMed and Web of Science, were exhaustively searched using search terms and synonyms, resulting in 608 identified peer-reviewed papers. Based on the inclusion criteria, 15 papers were included in the final review. The inclusion criteria included papers published between March 2020 and January 2023 and references to urban settings and COVID-19 in the papers. Several studies clearly documented a backsliding of coverage in urban and peri-urban settings, with some predictors or challenges to optimum coverage as well as some pro-equity strategies deployed or recommended in these studies. This emphasizes the need to focus on context-specific routine immunization catch-up and recovery strategies to suit the peculiarities of urban areas to get countries back on track toward achieving the targets of the IA2030. While more evidence is needed around the impact of the pandemic in urban areas, utilizing tools and platforms created to support advancing the equity agenda is pivotal. We posit that a renewed focus on urban immunization is critical if we are to achieve the IA2030 targets. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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12 pages, 612 KiB  
Review
Equity-Informative Economic Evaluations of Vaccines: A Systematic Literature Review
by Chanthawat Patikorn, Jeong-Yeon Cho, Philipp Lambach, Raymond Hutubessy and Nathorn Chaiyakunapruk
Vaccines 2023, 11(3), 622; https://doi.org/10.3390/vaccines11030622 - 09 Mar 2023
Cited by 1 | Viewed by 2152
Abstract
The Immunization Agenda 2030 prioritizes the populations without access to vaccines. Health equity has been increasingly incorporated into economic evaluations of vaccines to foster equitable access. Robust and standardized methods are needed to evaluate the health equity impact of vaccination programs to ensure [...] Read more.
The Immunization Agenda 2030 prioritizes the populations without access to vaccines. Health equity has been increasingly incorporated into economic evaluations of vaccines to foster equitable access. Robust and standardized methods are needed to evaluate the health equity impact of vaccination programs to ensure monitoring and effective addressing of inequities. However, methods currently in place vary and potentially affect the application of findings to inform policy decision-making. We performed a systematic review by searching PubMed, Embase, Econlit, and the CEA Registry up to 15 December 2022 to identify equity-informative economic evaluations of vaccines. Twenty-one studies were included that performed health equity impact analysis to estimate the distributional impact of vaccines, such as deaths averted and financial risk protection, across equity-relevant subgroups. These studies showed that the introduction of vaccines or improved vaccination coverage resulted in fewer deaths and higher financial risk benefits in subpopulations with higher disease burdens and lower vaccination coverage—particularly poorer income groups and those living in rural areas. In conclusion, methods to incorporate equity have been evolving progressively. Vaccination programs can enhance equity if their design and implementation address existing inequities in order to provide equitable vaccination coverage and achieve health equity. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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15 pages, 637 KiB  
Review
Within-Country Inequality in COVID-19 Vaccination Coverage: A Scoping Review of Academic Literature
by Nicole Bergen, Nicole E. Johns, Diana Chang Blanc and Ahmad Reza Hosseinpoor
Vaccines 2023, 11(3), 517; https://doi.org/10.3390/vaccines11030517 - 23 Feb 2023
Cited by 3 | Viewed by 2091
Abstract
Since December 2020, COVID-19 vaccines have become increasingly available to populations around the globe. A growing body of research has characterised inequalities in COVID-19 vaccination coverage. This scoping review aims to locate, select and assess research articles that report on within-country inequalities in [...] Read more.
Since December 2020, COVID-19 vaccines have become increasingly available to populations around the globe. A growing body of research has characterised inequalities in COVID-19 vaccination coverage. This scoping review aims to locate, select and assess research articles that report on within-country inequalities in COVID-19 vaccination coverage, and to provide a preliminary overview of inequality trends for selected dimensions of inequality. We applied a systematic search strategy across electronic databases with no language or date restrictions. Our inclusion criteria specified research articles or reports that analysed inequality in COVID-19 vaccination coverage according to one or more socioeconomic, demographic or geographic dimension of inequality. We developed a data extraction template to compile findings. The scoping review was carried out using the PRISMA-ScR checklist. A total of 167 articles met our inclusion criteria, of which half (n = 83) were conducted in the United States. Articles focused on vaccine initiation, full vaccination and/or receipt of booster. Diverse dimensions of inequality were explored, most frequently relating to age (n = 127 articles), race/ethnicity (n = 117 articles) and sex/gender (n = 103 articles). Preliminary assessments of inequality trends showed higher coverage among older population groups, with mixed findings for sex/gender. Global research efforts should be expanded across settings to understand patterns of inequality and strengthen equity in vaccine policies, planning and implementation. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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Other

7 pages, 243 KiB  
Commentary
Addressing Determinants of Immunization Inequities Requires Objective Tools to Devise Local Solutions
by Siddhartha Sankar Datta, Federico Martinón-Torres, Nino Berdzuli, Niyazi Cakmak, Michael Edelstein, Simon Cottrell and Mark Muscat
Vaccines 2023, 11(4), 811; https://doi.org/10.3390/vaccines11040811 - 06 Apr 2023
Cited by 1 | Viewed by 1594
Abstract
Universal immunization substantially reduces morbidity and mortality from vaccine-preventable diseases. In recent years, routine immunization coverage has varied considerably among countries across the WHO European Region, and among different populations and districts within countries. It has even declined in some countries. Sub-optimal immunization [...] Read more.
Universal immunization substantially reduces morbidity and mortality from vaccine-preventable diseases. In recent years, routine immunization coverage has varied considerably among countries across the WHO European Region, and among different populations and districts within countries. It has even declined in some countries. Sub-optimal immunization coverage contributes to accumulations of susceptible individuals and can lead to outbreaks of vaccine-preventable diseases. The European Immunization Agenda 2030 (EIA2030) seeks to build better health in the WHO European Region by ensuring equity in immunization and supporting immunization stakeholders in devising local solutions to local challenges. The factors that influence routine immunization uptake are context specific and multifactorial; addressing immunization inequities will require overcoming or removing barriers to vaccination for underserved individuals or populations. Local level immunization stakeholders must first identify the underlying causes of inequities, and based on this information, tailor resources, or service provision to the local context, as per the organization and characteristics of the health care system in their countries. To do this, in addition to using the tools already available to broadly identify immunization inequities at the national and regional levels, they will need new pragmatic guidance and tools to address the identified local challenges. It is time to develop the necessary guidance and tools and support immunization stakeholders at all levels, especially those at the subnational or local health centre levels, to make the vision of EIA2030 a reality. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
8 pages, 1273 KiB  
Opinion
Addressing Immunization Inequity—What Have the International Community and India Learned over 35 Years?
by Lora Shimp, Raj Shankar Ghosh and Katharine Elkes
Vaccines 2023, 11(4), 790; https://doi.org/10.3390/vaccines11040790 - 04 Apr 2023
Cited by 2 | Viewed by 2319
Abstract
Countries around the world established immunization programs over 40 years ago to reach all infants. The maturity of these preventive health programs offers some useful learning on the importance of, and components needed for, population-based services to reach all communities. A public health [...] Read more.
Countries around the world established immunization programs over 40 years ago to reach all infants. The maturity of these preventive health programs offers some useful learning on the importance of, and components needed for, population-based services to reach all communities. A public health success, ensuring equity in immunization, requires a multi-faceted approach that includes sustained government and partner commitment and human, financial, and program operational resources. Evidence from India’s Universal Immunization Program (UIP) across stabilizing vaccine supply and services, enhancing access, and generating demand for vaccines in the community provides a useful case study. The political leadership in India took advantage of the two decades of learning from polio eradication and focused initiatives, such as the National Health Mission and Intensified Mission Indradhanush, to reach populations with immunization services. With a goal of leaving no one behind, India’s UIP and partners are bringing essential rotavirus and pneumococcal vaccines nationwide, upgrading vaccine cold chain and supply systems with technologies, such as the electronic Vaccine Intelligence Network (eVIN), and optimizing funding for local needs through the Program Implementation Plan (PIP) budgetary processes and building health worker capacities through training, awareness, and e-learning. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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9 pages, 890 KiB  
Perspective
Why Reaching Zero-Dose Children Holds the Key to Achieving the Sustainable Development Goals
by Dan Hogan and Anuradha Gupta
Vaccines 2023, 11(4), 781; https://doi.org/10.3390/vaccines11040781 - 31 Mar 2023
Cited by 15 | Viewed by 4513
Abstract
Immunization has one of the highest coverage levels of any health intervention, yet there remain zero-dose children, defined as those who do not receive any routine immunizations. There were 18.2 million zero-dose children in 2021, and as they accounted for over 70% of [...] Read more.
Immunization has one of the highest coverage levels of any health intervention, yet there remain zero-dose children, defined as those who do not receive any routine immunizations. There were 18.2 million zero-dose children in 2021, and as they accounted for over 70% of all underimmunized children, reaching zero-dose children will be essential to meeting ambitious immunization coverage targets by 2030. While certain geographic locations, such as urban slum, remote rural, and conflict-affected settings, may place a child at higher risk of being zero-dose, zero-dose children are found in many places, and understanding the social, political, and economic barriers they face will be key to designing sustainable programs to reach them. This includes gender-related barriers to immunization and, in some countries, barriers related to ethnicity and religion, as well as the unique challenges associated with reaching nomadic, displaced, or migrant populations. Zero-dose children and their families face multiple deprivations related to wealth, education, water and sanitation, nutrition, and access to other health services, and they account for one-third of all child deaths in low- and middle-income countries. Reaching zero-dose children and missed communities is therefore critical to achieving the Sustainable Development Goals commitment to “leave no one behind”. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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7 pages, 416 KiB  
Opinion
Recovering from the Unprecedented Backsliding in Immunization Coverage: Learnings from Country Programming in Five Countries through the Past Two Years of COVID-19 Pandemic Disruptions
by Anithasree Athiyaman, Tosin Ajayi, Faith Mutuku, Fredrick Luwaga, Sarah Bryer, Omotayo Giwa, Shadrack Mngemane, Nnang Nadege Edwige and Leslie Berman
Vaccines 2023, 11(2), 375; https://doi.org/10.3390/vaccines11020375 - 07 Feb 2023
Cited by 5 | Viewed by 2732
Abstract
Between 2020 and 2021, the COVID-19 pandemic severely strained health systems across countries, leaving millions without access to essential healthcare services. Immunization programs experienced a ‘double burden’ of challenges: initial pandemic-related lockdowns disrupted access to routine immunization services, while subsequent COVID-19 vaccination efforts [...] Read more.
Between 2020 and 2021, the COVID-19 pandemic severely strained health systems across countries, leaving millions without access to essential healthcare services. Immunization programs experienced a ‘double burden’ of challenges: initial pandemic-related lockdowns disrupted access to routine immunization services, while subsequent COVID-19 vaccination efforts shifted often limited resources away from routine services. The latest World Health Organization (WHO) and United Nations Children’s Fund (UNICEF) estimates suggest that 25 million children did not receive routine vaccinations in 2021, six million more than in 2019 and the highest number witnessed in nearly two decades. Recovering from this sobering setback requires a united push on several fronts. Intensifying the catch-up of routine immunization services is critical to reach children left behind during the pandemic and bridge large immunity gaps in countries. At the same time, we must strengthen the resilience of immunization systems to withstand future pandemics if we hope to achieve the goals of Immunization Agenda 2030 to ensure vaccinations are available for everyone, everywhere by 2030. In this article, leveraging the key actions for sustainable global immunization progress as a framework, we spotlight examples of strategies used by five countries—Cambodia, Cameroon, Kenya, Nigeria, and Uganda—who have exhibited exemplar performance in strengthening routine immunization programs and restored lost coverage levels in the last two years of the COVID-19 pandemic. The contents of this article will be helpful for countries seeking to maintain, restore, and strengthen their immunization services and catch up missed children in the context of pandemic recovery and to direct their focus toward building back a better resilience of their immunization systems to respond more rapidly and effectively, despite new and emerging challenges. Full article
(This article belongs to the Special Issue Inequality in Immunization 2023)
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