Vaccines

20 pages, 319 KiB

Open AccessArticle

Attitudes towards the COVID-19 Vaccine and Willingness to Get Vaccinated among Healthcare Workers in French Guiana: The Influence of Geographical Origin

by Nicolas Vignier, Kepha Brureau, Sybille Granier, Jacques Breton, Céline Michaud, Mélanie Gaillet, Camille Agostini, Mathilde Ballet, Mathieu Nacher, Audrey Valdes, Philippe Abboud, Antoine Adenis, Félix Djossou, Loïc Epelboin and Maylis Douine

Vaccines 2021, 9(6), 682; https://doi.org/10.3390/vaccines9060682 - 21 Jun 2021

Cited by 28 | Viewed by 4582

Abstract

Background: In the context of the global COVID-19 pandemic and the expansion of the more transmissible 20J/501Y.V3 (Gamma) variant of concern (VOC), mRNA vaccines have been made available in French Guiana, an overseas French territory in South America, from mid-January 2021. This study [...] Read more.

Background: In the context of the global COVID-19 pandemic and the expansion of the more transmissible 20J/501Y.V3 (Gamma) variant of concern (VOC), mRNA vaccines have been made available in French Guiana, an overseas French territory in South America, from mid-January 2021. This study aimed to estimate the willingness to be vaccinated and the socio-demographic and motivational correlates among Health Care Workers (HCWs) in French Guiana. Methods: A cross-sectional survey was conducted from January 22 to March 26, 2021 among a sample of HCWs in French Guiana. They were asked about their willingness to get vaccinated against COVID-19 and vaccine hesitancy, vaccine uptake and vaccines attitudes. Factors associated with willingness to get vaccinated have been analyzed with ordinal logistic regression, using Stata software. Results: A total of 579 HCWs were interviewed, including 220 physicians and 200 nurses most often working in hospital (54%) or in the liberal sector (22%). Overall, 65.6% of respondents reported that they were willing or had already been vaccinated against COVID-19, while 24.3% of respondents reported that they did not want to get vaccinated against COVID-19 and 11.2% were unsure. HCWs were more willing to get vaccine if they were older, were worried about COVID-19 and were confident in the management of epidemic. Conversely, participants were less likely to have been vaccinated or willing to if they were nurses or of another non-medical profession, born in French Guiana, feared adverse effects, or if they did not trust pharmaceutical companies and management of the epidemic by authorities. Conclusion: Negative attitudes towards vaccines are a major public health concern among HCWs in French Guiana when considering the current active epidemic with Gamma VOC. General vaccine hesitancy and concerns about future side effects in particular represent important barriers. Low confidence in government and science are significant in COVID-19 vaccine refusal among non-medical staffs. Public health messaging with information on vaccine safety should be tailored to address these concerns. The specific challenges of HCWs from French Guiana must be taken into account. Full article

(This article belongs to the Special Issue SARS-CoV-2 (COVID-19) Vaccination and Compliance/Hesitancy)

12 pages, 1535 KiB

Open AccessArticle

Immunization Catch-Up for Newly Arrived Migrants in France: A Cross-Sectional Study among French General Practitioners

by Sohela Moussaoui, Anne Marie Aurousseau, Sylvain Nappez, Julian Cornaglia, Gaylord Delobre, Sophie Blanchi, Louise Luan, Stéphanie Vandentorren, Olivier Bouchaud, Odile Launay, Louise Nutte, Roxane Liard, Mariela Skendi, Matthieu Mechain and Nicolas Vignier

Vaccines 2021, 9(6), 681; https://doi.org/10.3390/vaccines9060681 - 21 Jun 2021

Cited by 4 | Viewed by 1885

Abstract

Background: Migrants often undergo an incomplete vaccination program in regards to the French recommendations. The aim of this study was to evaluate the practices of French General Practitioners’ (GPs) in terms of catch-up vaccination. Methods: A cross-sectional study was carried-out in 2017–2018 in [...] Read more.

Background: Migrants often undergo an incomplete vaccination program in regards to the French recommendations. The aim of this study was to evaluate the practices of French General Practitioners’ (GPs) in terms of catch-up vaccination. Methods: A cross-sectional study was carried-out in 2017–2018 in France. An online questionnaire was disseminated by email through scholarly societies to GPs involved in the care and the vaccination of migrants. Analyses included univariate and multivariate analysis with a logistic regression model. Results: A total of 216 GPs completed the survey. A majority identified themselves with an average level regarding the prevention of infectious diseases among migrant populations (56.7%) and confirmed this is part of their daily practice (83.3%). The majority of respondents do not perform more than two injections on the same day. When compared to GPs working in health centres, those with a private practice are more likely to report returning to a full primary vaccination schedule (adjusted OR = 2.90, 95% CI [1.29–6.53]). Aside from the serology for hepatitis B and to a lesser extent for measles, other pre-vaccination serologies were not frequently used by GPs. When a migrant declares to be up-to-date with his immunisations, only 56.5% of doctors consider this information reliable. Conclusions: This study clarified the vaccination practices of GPs receiving migrant patients in consultation and showed its heterogeneity. An important need for benchmarks has been identified and these results were used for the elaboration of the French guidelines on vaccines catch-up. Full article

(This article belongs to the Section Human Vaccines and Public Health)

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33 pages, 4007 KiB

Open AccessReview

Therapeutic Potential of HLA-I Polyreactive mAbs Mimicking the HLA-I Polyreactivity and Immunoregulatory Functions of IVIg

by Mepur H. Ravindranath, Fatiha El Hilali and Edward J. Filippone

Vaccines 2021, 9(6), 680; https://doi.org/10.3390/vaccines9060680 - 21 Jun 2021

Cited by 2 | Viewed by 2722

Abstract

HLA class-I (HLA-I) polyreactive monoclonal antibodies (mAbs) reacting to all HLA-I alleles were developed by immunizing mice with HLA-E monomeric, α-heavy chain (αHC) open conformers (OCs). Two mAbs (TFL-006 and TFL-007) were bound to the αHC’s coated on a solid matrix. The binding [...] Read more.

HLA class-I (HLA-I) polyreactive monoclonal antibodies (mAbs) reacting to all HLA-I alleles were developed by immunizing mice with HLA-E monomeric, α-heavy chain (αHC) open conformers (OCs). Two mAbs (TFL-006 and TFL-007) were bound to the αHC’s coated on a solid matrix. The binding was inhibited by the peptide ¹¹⁷AYDGKDY¹²³, present in all alleles of the six HLA-I isoforms but masked by β2-microglobulin (β2-m) in intact HLA-I trimers (closed conformers, CCs). IVIg preparations administered to lower anti-HLA Abs in pre-and post-transplant patients have also shown HLA-I polyreactivity. We hypothesized that the mAbs that mimic IVIg HLA-I polyreactivity might also possess the immunomodulatory capabilities of IVIg. We tested the relative binding affinities of the mAbs and IVIg for both OCs and CCs and compared their effects on (a) the phytohemagglutinin (PHA)-activation T-cells; (b) the production of anti-HLA-II antibody (Ab) by B-memory cells and anti-HLA-I Ab by immortalized B-cells; and (c) the upregulation of CD4+, CD25+, and Fox P³+ T-regs. The mAbs bound only to OC, whereas IVIg bound to both CC and OC. The mAbs suppressed blastogenesis and proliferation of PHA-activated T-cells and anti-HLA Ab production by B-cells and expanded T-regs better than IVIg. We conclude that a humanized version of the TFL-mAbs could be an ideal, therapeutic IVIg-mimetic. Full article

(This article belongs to the Collection Research on Monoclonal Antibodies and Antibody Engineering)

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19 pages, 926 KiB

Open AccessReview

Overwhelming Evidence for a Major Role for Herpes Simplex Virus Type 1 (HSV1) in Alzheimer’s Disease (AD); Underwhelming Evidence against

by Ruth F. Itzhaki

Vaccines 2021, 9(6), 679; https://doi.org/10.3390/vaccines9060679 - 21 Jun 2021

Cited by 46 | Viewed by 7932

Abstract

This review describes investigations of specific topics that lie within the general subject of HSV1’s role in AD/dementia, published in the last couple of years. They include studies on the following: relationship of HSV1 to AD using neural stem cells; the apparent protective [...] Read more.

This review describes investigations of specific topics that lie within the general subject of HSV1’s role in AD/dementia, published in the last couple of years. They include studies on the following: relationship of HSV1 to AD using neural stem cells; the apparent protective effects of treatment of HSV1 infection or of VZV infection with antivirals prior to the onset of dementia; the putative involvement of VZV in AD/dementia; the possible role of human herpes virus 6 (HHV6) in AD; the seemingly reduced risk of dementia after vaccination with diverse types of vaccine, and the association shown in some vaccine studies with reduced frequency of HSV1 reactivation; anti-HSV serum antibodies supporting the linkage of HSV1 in brain with AD in APOE-ε4 carriers, and the association between APOE and cognition, and association of APOE and infection with AD/dementia. The conclusions are that there is now overwhelming evidence for HSV1’s role—probably causal—in AD, when it is present in brain of APOE-ε4 carriers, and that further investigations should be made on possible prevention of the disease by vaccination, or by prolonged antiviral treatment of HSV1 infection in APOE-ε4 carriers, before disease onset. Full article

(This article belongs to the Special Issue Role of HSV-1 and Host Immune Response on Neurodegenerative Diseases)

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10 pages, 567 KiB

Open AccessArticle

COVID-19 Vaccine Acceptance in Azuay Province, Ecuador: A Cross-Sectional Online Survey

by Julio Jaramillo-Monge, Michael Obimpeh, Bernardo Vega, David Acurio, Annelies Boven, Veronique Verhoeven and Robert Colebunders

Vaccines 2021, 9(6), 678; https://doi.org/10.3390/vaccines9060678 - 21 Jun 2021

Cited by 13 | Viewed by 4213

Abstract

We investigated the COVID-19 vaccination acceptance level in Azuay province, Ecuador through an online survey from 12th to 26th February (before the start of the COVID-19 vaccination campaign in Ecuador). Overall, 1219 respondents participated in the survey. The mean age was 32 ± [...] Read more.

We investigated the COVID-19 vaccination acceptance level in Azuay province, Ecuador through an online survey from 12th to 26th February (before the start of the COVID-19 vaccination campaign in Ecuador). Overall, 1219 respondents participated in the survey. The mean age was 32 ± 13 years; 693 participants (57%) were female. In total, 1109 (91%) of the participants indicated they were willing to be vaccinated with a COVID-19 vaccine, if the vaccine is at least 95% effective; 835 (68.5%) if it is 90% effective and 493 (40.5%) if it is 70% effective; 676 (55.5%) participants indicated they feared side effects and 237 (19.4%) thought the vaccine was not effective. Older age, having had a postgraduate education, a history of a negative COVID-19 test, a high level of worry of contracting COVID-19, believing that COVID-19 infection can be prevented with a vaccine and understanding there is currently an effective vaccine against COVID-19 were associated with higher vaccination acceptance. A vaccination education campaign will be needed to increase the knowledge of Ecuadorians about the COVID-19 vaccine and to increase their trust in the vaccine. People with a lower education level and living in rural areas may need to be targeted during such a campaign. Full article

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8 pages, 705 KiB

Open AccessPerspective

Evaluating Functional Immunity Following Encapsulated Bacterial Infection and Vaccination

by Zheng Quan Toh, Rachel A. Higgins, Nadia Mazarakis, Elysia Abbott, Jordan Nathanielsz, Anne Balloch, Kim Mulholland and Paul V. Licciardi

Vaccines 2021, 9(6), 677; https://doi.org/10.3390/vaccines9060677 - 20 Jun 2021

Cited by 2 | Viewed by 5417

Abstract

Encapsulated bacteria such as Streptococcus pneumoniae, Haemophilus influenzae type b and Neisseria meningitidis cause significant morbidity and mortality in young children despite the availability of vaccines. Highly specific antibodies are the primary mechanism of protection against invasive disease. Robust and standardised assays [...] Read more.

Encapsulated bacteria such as Streptococcus pneumoniae, Haemophilus influenzae type b and Neisseria meningitidis cause significant morbidity and mortality in young children despite the availability of vaccines. Highly specific antibodies are the primary mechanism of protection against invasive disease. Robust and standardised assays that measure functional antibodies are also necessary for vaccine evaluation and allow for the accurate comparison of data between clinical studies. This mini review describes the current state of functional antibody assays and their importance in measuring protective immunity. Full article

(This article belongs to the Special Issue Vaccine Evaluation Methods and Studies)

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12 pages, 703 KiB

Open AccessArticle

Influenza Illness and Partial Vaccination in the First Two Years of Life

by Abram L. Wagner, Lionel Gresh, Nery Sanchez, Guillermina Kuan, John Kubale, Roger Lopez, Sergio Ojeda, Eduardo Azziz-Baumgartner, Angel Balmaseda and Aubree Gordon

Vaccines 2021, 9(6), 676; https://doi.org/10.3390/vaccines9060676 - 20 Jun 2021

Cited by 2 | Viewed by 2071

Abstract

More information about influenza in low- and middle-income countries could guide the establishment of pediatric influenza vaccine programs. This study (1) characterizes the burden of influenza in infants, and (2) compares signs and symptoms by prior influenza vaccination or influenza illness. Newborns from [...] Read more.

More information about influenza in low- and middle-income countries could guide the establishment of pediatric influenza vaccine programs. This study (1) characterizes the burden of influenza in infants, and (2) compares signs and symptoms by prior influenza vaccination or influenza illness. Newborns from Managua, Nicaragua, were followed for two years. Data came from primary medical appointments, PCR testing, and parents’ daily symptom diaries. Logistic regression models estimated associations between preceding vaccination or illness and influenza incidence. Linear models compared duration of illness by prior vaccination or influenza illness. Among 833 infants, 31% had PCR-positive influenza, and 28% were vaccinated against influenza. Four (<0.5%) were fully vaccinated. Overall, influenza incidence was 21.0 (95% confidence interval (CI): 18.8, 23.2) per 100 person-years. Incidence was lower among those with prior influenza compared with those without preceding illness or vaccination (OR: 0.64, 95% CI: 0.44, 0.94). Partially vaccinated children had 1 day less fever than those without prior illness or vaccination (p = 0.049). A large proportion of children <2 years in Nicaragua contract influenza. Illness was attenuated for those partially vaccinated. Since few children were fully vaccinated, future studies will need to consider the effectiveness of a two-dose vaccination schedule. Full article

(This article belongs to the Section Epidemiology)

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9 pages, 1296 KiB

Open AccessCommunication

Evaluation of SARS-CoV-2 Spike Protein Antibody Titers in Cord Blood after COVID-19 Vaccination during Pregnancy in Polish Healthcare Workers: Preliminary Results

by Wojciech Zdanowski and Tomasz Waśniewski

Vaccines 2021, 9(6), 675; https://doi.org/10.3390/vaccines9060675 - 19 Jun 2021

Cited by 41 | Viewed by 8719

Abstract

Background: The coronavirus disease 2019 (COVID-19) pandemic has given rise to the need to develop a vaccine as quickly as possible. As pregnant women are at increased risk of contracting severe COVID-19, with higher mortality, it is essential to assess the safety of [...] Read more.

Background: The coronavirus disease 2019 (COVID-19) pandemic has given rise to the need to develop a vaccine as quickly as possible. As pregnant women are at increased risk of contracting severe COVID-19, with higher mortality, it is essential to assess the safety of the vaccines administered during pregnancy. Methods: The aim of this study was to determine the titer of specific maternal and cord antibodies against severe acute respiratory syndrome coronavirus 2 S protein after antenatal vaccination. The secondary objective was to evaluate the ratio of the umbilical cord to the maternal antibody titers. Patients included in the study were enrolled after undergoing voluntary vaccination against COVID-19 during pregnancy at different weeks of gestation. All patients analyzed in our initial study were vaccinated with the BNT162b2 mRNA COVID-19 vaccine. Results: The results of the current study document high anti-S total IgG antibody titers in cord serum at birth in all mother–infant pairs analyzed. The mean umbilical cord blood sample IgG antibody titer anti-S protein was 1026.51 U/mL (±SD 769.25). The mean cord-to-maternal anti–S IgG antibody ratio was 1.28 (±SD 0.798). A significant positive correlation was observed between the week of gestation at which the first dose was administered and the week of gestation at which the second dose was administered, and the respective cord-to-maternal ratio (r = 0.48; p = 0.0029) for the first dose and (r = 0.39; p = 0.0102) for the second dose. Conclusions: To date, despite the prevalence of COVID-19 vaccination, there is a lack of conclusive evidence supporting the safety and efficacy of vaccination of pregnant women. Therefore, the results we present are complementary. Our study suggests that maternal immunization may provide neonatal protection through the transplacental transfer of antibodies. Of particular importance is the demonstration that antibody transfer is correlated with the time from vaccination to delivery, which may allow future determination of the optimal timing of COVID-19 vaccination in pregnant women. Full article

(This article belongs to the Collection COVID-19 Vaccines and Vaccination)

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8 pages, 235 KiB

Open AccessArticle

Evaluation of Side Effects Associated with COVID-19 Vaccines in Saudi Arabia

by Abdulaziz Alhazmi, Edrous Alamer, Dalia Daws, Mashael Hakami, Majid Darraj, Siddig Abdelwahab, Amani Maghfuri and Abdullah Algaissi

Vaccines 2021, 9(6), 674; https://doi.org/10.3390/vaccines9060674 - 18 Jun 2021

Cited by 101 | Viewed by 11698

Abstract

Background: Pfizer-BioNTech and Oxford-AstraZeneca are recently introduced vaccines to combat COVID-19 pandemic. During clinical trials, mild to moderate side effects have been associated with these vaccines. Thus, we aimed to evaluate short-term post-vaccination side effects. Methods: Cross-sectional, retrospective study using an online questionnaire [...] Read more.

Background: Pfizer-BioNTech and Oxford-AstraZeneca are recently introduced vaccines to combat COVID-19 pandemic. During clinical trials, mild to moderate side effects have been associated with these vaccines. Thus, we aimed to evaluate short-term post-vaccination side effects. Methods: Cross-sectional, retrospective study using an online questionnaire was conducted among COVID-19 vaccines recipients in Saudi Arabia. General and demographic data were collected, and vaccine-associated side effects after receiving at least one dose of each vaccine were evaluated. Results: Our final sample consisted of 515 participants with a median age of 26 years. Most of the study participants were female (57%). Nearly 13% of the study subjects have reported previous infections with SARS-CoV-2. Oxford-AstraZeneca and Pfizer-BioNTech vaccines have been received by 75% and 25% of the study participants, respectively. Side effects associated with COVID-19 vaccines have been reported by 60% of the study subjects, and most of them reported fatigue (90%), pain at the site of the injections (85%). Conclusion: Side effects that are reported post Oxford-AstraZeneca and Pfizer-BioNTech vaccines among our study participants are not different from those that were reported in the clinical trials, indicating safe profiles for both vaccines. Further studies are needed to evaluate the effectiveness of the current vaccines in protection against SARS-CoV-2 reinfections. Full article

12 pages, 299 KiB

Open AccessArticle

Safety of ChAdOx1 nCoV-19 Vaccine: Independent Evidence from Two EU States

by Abanoub Riad, Andrea Pokorná, Mohamed Mekhemar, Jonas Conrad, Jitka Klugarová, Michal Koščík, Miloslav Klugar and Sameh Attia

Vaccines 2021, 9(6), 673; https://doi.org/10.3390/vaccines9060673 - 18 Jun 2021

Cited by 50 | Viewed by 3794

Abstract

Recent reports of thrombosis following AstraZeneca COVID-19 vaccine in young females (<55 years-old) led to temporary suspension and urgent investigation by the European Medicines Agency (EMA) that concluded that vaccine benefits still outweigh its side effects (SEs). Therefore, this study aims to provide [...] Read more.

Recent reports of thrombosis following AstraZeneca COVID-19 vaccine in young females (<55 years-old) led to temporary suspension and urgent investigation by the European Medicines Agency (EMA) that concluded that vaccine benefits still outweigh its side effects (SEs). Therefore, this study aims to provide early independent evidence on the vaccine SEs’ prevalence and their potential risk factors; a cross-sectional survey-based study was carried out between February and March 2021 in Germany and Czech Republic among healthcare workers who recently received the AstraZeneca COVID-19 vaccine. The study used a validated self-administered questionnaire composed of twenty-eight multiple-choice items covering demographic variables, medical anamneses, and local, systemic, oral, and skin related SEs of the vaccine. Out of the ninety-two included participants, 77.2% were females and 79.3% were from Germany. Their mean age was 35.37 ± 12.62 (19–64) years-old, 15.2% had chronic illnesses and 22.8% were receiving medical treatments. Overall, 94.6% of the participants reported at least one SE. The most common local SE was injection site pain (72.8%), and the most common systemic SEs were fatigue (73.9%), muscle pain (55.4%), chills (48.9%), feeling unwell (46.7%), nausea (45.7%), and headache (29.3%). The vast majority (91.9%) resolved within 1–3 days, and the below 35 years-old group was the least affected age group. The SEs’ frequency was insignificantly higher in females and previously infected participants; the vaccine safety for the elderly was supported by the early findings of this study. Chronic illnesses and medical treatments were not associated with an increased risk of SE incidence and frequency. No blood disorder SEs were reported in our sample. Further independent studies are highly required to evaluate the safety of the AstraZeneca vaccine and to explore whether gender or previous infection could be associated with the vaccine SEs. Full article

(This article belongs to the Section COVID-19 Vaccines and Vaccination)

9 pages, 1607 KiB

Open AccessArticle

BNT162b2 mRNA SARS-CoV-2 Vaccine Elicits High Avidity and Neutralizing Antibodies in Healthcare Workers

by Federico Pratesi, Teresita Caruso, Davide Testa, Tiziano Tarpanelli, Alessandra Gentili, Davide Gioè and Paola Migliorini

Vaccines 2021, 9(6), 672; https://doi.org/10.3390/vaccines9060672 - 18 Jun 2021

Cited by 28 | Viewed by 3497

Abstract

The BNT162b2 vaccine, containing lipid nanoparticles-formulated mRNA encoding the full-length spike protein of SARS-CoV-2, has been employed to immunize health care workers in Italy, administered in two doses 21 days apart. In this study, we characterized the antibody response induced by the BNT162b2 [...] Read more.

The BNT162b2 vaccine, containing lipid nanoparticles-formulated mRNA encoding the full-length spike protein of SARS-CoV-2, has been employed to immunize health care workers in Italy, administered in two doses 21 days apart. In this study, we characterized the antibody response induced by the BNT162b2 vaccine in a group of health care workers, tested at baseline, after the first dose and after the booster. Thirty-nine subjects without previous exposure to SARS-CoV-2 were vaccinated with the BNT162b2 vaccine. IgM, IgG, and IgA anti-receptor binding domain (RBD) were tested by ELISA. Neutralizing antibodies were evaluated testing the inhibition of RBD binding to ACE2. Antibody avidity was measured by urea avidity ELISA. IgM anti-RBD are produced after the first dose of vaccine and persist after the booster. IgG and IgA anti-RBD antibodies are detected in high amounts in all the subjects after the first dose and further increase after the booster. A few subjects, already after the first dose, produce antibodies inhibiting RBD interaction with ACE2. After the booster, high levels of inhibitory antibodies are detected in all the subjects. Affinity maturation takes place with boosting and IgG anti-RBD avidity increases with the number of immunizations. A less pronounced increase is observed with IgA. These data indicate that the BNT162b2 vaccine can induce high levels of protective antibodies of high avidity in vaccinated subjects; both IgG and IgA anti-RBD antibodies are produced. Further studies are needed to evaluate antibody persistence over time. Full article

(This article belongs to the Section COVID-19 Vaccines and Vaccination)

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12 pages, 1263 KiB

Open AccessReview

What Constitutes Protective Immunity Following Yellow Fever Vaccination?

by Jolynne Mokaya, Derick Kimathi, Teresa Lambe and George M. Warimwe

Vaccines 2021, 9(6), 671; https://doi.org/10.3390/vaccines9060671 - 18 Jun 2021

Cited by 7 | Viewed by 2863

Abstract

Yellow fever (YF) remains a threat to global health, with an increasing number of major outbreaks in the tropical areas of the world over the recent past. In light of this, the Eliminate Yellow Fever Epidemics Strategy was established with the aim of [...] Read more.

Yellow fever (YF) remains a threat to global health, with an increasing number of major outbreaks in the tropical areas of the world over the recent past. In light of this, the Eliminate Yellow Fever Epidemics Strategy was established with the aim of protecting one billion people at risk of YF through vaccination by the year 2026. The current YF vaccine gives excellent protection, but its use is limited by shortages in supply due to the difficulties in producing the vaccine. There are good grounds for believing that alternative fractional dosing regimens can produce strong protection and overcome the problem of supply shortages as less vaccine is required per person. However, immune responses to these vaccination approaches are yet to be fully understood. In addition, published data on immune responses following YF vaccination have mostly quantified neutralising antibody titers. However, vaccine-induced antibodies can confer immunity through other antibody effector functions beyond neutralisation, and an effective vaccine is also likely to induce strong and persistent memory T cell responses. This review highlights the gaps in knowledge in the characterisation of YF vaccine-induced protective immunity in the absence or presence of neutralising antibodies. The assessment of biophysical antibody characteristics and cell-mediated immunity following YF vaccination could help provide a comprehensive landscape of YF vaccine-induced immunity and a better understanding of correlates of protective immunity. Full article

(This article belongs to the Special Issue Vaccines for Infectious and Chronic Diseases)

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19 pages, 1168 KiB

Open AccessReview

Immunization and Immunotherapy Approaches against Pseudomonas aeruginosa and Burkholderia cepacia Complex Infections

by Sílvia A. Sousa, António M. M. Seixas, Joana M. M. Marques and Jorge H. Leitão

Vaccines 2021, 9(6), 670; https://doi.org/10.3390/vaccines9060670 - 18 Jun 2021

Cited by 15 | Viewed by 4699

Abstract

Human infections caused by the opportunist pathogens Burkholderia cepacia complex and Pseudomonas aeruginosa are of particular concern due to their severity, their multiple antibiotic resistance, and the limited eradication efficiency of the current available treatments. New therapeutic options have been pursued, being vaccination [...] Read more.

Human infections caused by the opportunist pathogens Burkholderia cepacia complex and Pseudomonas aeruginosa are of particular concern due to their severity, their multiple antibiotic resistance, and the limited eradication efficiency of the current available treatments. New therapeutic options have been pursued, being vaccination strategies to prevent or limit these infections as a rational approach to tackle these infections. In this review, immunization and immunotherapy approaches currently available and under study against these bacterial pathogens is reviewed. Ongoing active and passive immunization clinical trials against P. aeruginosa infections is also reviewed. Novel identified bacterial targets and their possible exploitation for the development of immunization and immunotherapy strategies against P. aeruginosa and B. cepacia complex and infections are also presented and discussed. Full article

(This article belongs to the Special Issue Advances in Vaccine Development)

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13 pages, 3404 KiB

Open AccessArticle

In Silico Prediction of a Multitope Vaccine against Moraxella catarrhalis: Reverse Vaccinology and Immunoinformatics

by Mohamed A. Soltan, Nada Elbassiouny, Helmy Gamal, Eslam B. Elkaeed, Refaat A. Eid, Muhammad Alaa Eldeen and Ahmed A. Al-Karmalawy

Vaccines 2021, 9(6), 669; https://doi.org/10.3390/vaccines9060669 - 18 Jun 2021

Cited by 55 | Viewed by 5907

Abstract

Moraxella catarrhalis (M. catarrhalis) is a Gram-negative bacterium that can cause serious respiratory tract infections and middle ear infections in children and adults. M. catarrhalis has demonstrated an increasing rate of antibiotic resistance in the last few years, thus development of [...] Read more.

Moraxella catarrhalis (M. catarrhalis) is a Gram-negative bacterium that can cause serious respiratory tract infections and middle ear infections in children and adults. M. catarrhalis has demonstrated an increasing rate of antibiotic resistance in the last few years, thus development of an effective vaccine is a major health priority. We report here a novel designed multitope vaccine based on the mapped epitopes of the vaccine candidates filtered out of the whole proteome of M. catarrhalis. After analysis of 1615 proteins using a reverse vaccinology approach, only two proteins (outer membrane protein assembly factor BamA and LPS assembly protein LptD) were nominated as potential vaccine candidates. These proteins were found to be essential, outer membrane, virulent and non-human homologs with appropriate molecular weight and high antigenicity score. For each protein, cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL) and B cell lymphocyte (BCL) epitopes were predicted and confirmed to be highly antigenic and cover conserved regions of the proteins. The mapped epitopes constituted the base of the designed multitope vaccine where suitable linkers were added to conjugate them. Additionally, beta defensin adjuvant and pan-HLA DR-binding epitope (PADRE) peptide were also incorporated into the construct to improve the stimulated immune response. The constructed multitope vaccine was analyzed for its physicochemical, structural and immunological characteristics and it was found to be antigenic, soluble, stable, non-allergenic and have a high affinity to its target receptor. Although the in silico analysis of the current study revealed that the designed multitope vaccine has the ability to trigger a specific immune response against M. catarrhalis, additional translational research is required to confirm the effectiveness of the designed vaccine. Full article

(This article belongs to the Special Issue Development of Epitope-Based Peptide Vaccine)

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30 pages, 1030 KiB

Open AccessReview

Cancer Vaccines: Promising Therapeutics or an Unattainable Dream

by Howard Donninger, Chi Li, John W. Eaton and Kavitha Yaddanapudi

Vaccines 2021, 9(6), 668; https://doi.org/10.3390/vaccines9060668 - 18 Jun 2021

Cited by 33 | Viewed by 4917

Abstract

The advent of cancer immunotherapy has revolutionized the field of cancer treatment and offers cancer patients new hope. Although this therapy has proved highly successful for some patients, its efficacy is not all encompassing and several cancer types do not respond. Cancer vaccines [...] Read more.

The advent of cancer immunotherapy has revolutionized the field of cancer treatment and offers cancer patients new hope. Although this therapy has proved highly successful for some patients, its efficacy is not all encompassing and several cancer types do not respond. Cancer vaccines offer an alternate approach to promote anti-tumor immunity that differ in their mode of action from antibody-based therapies. Cancer vaccines serve to balance the equilibrium of the crosstalk between the tumor cells and the host immune system. Recent advances in understanding the nature of tumor-mediated tolerogenicity and antigen presentation has aided in the identification of tumor antigens that have the potential to enhance anti-tumor immunity. Cancer vaccines can either be prophylactic (preventative) or therapeutic (curative). An exciting option for therapeutic vaccines is the emergence of personalized vaccines, which are tailor-made and specific for tumor type and individual patient. This review summarizes the current standing of the most promising vaccine strategies with respect to their development and clinical efficacy. We also discuss prospects for future development of stem cell-based prophylactic vaccines. Full article

(This article belongs to the Special Issue Cancer Vaccines and Immunotherapy for Tumor Prevention and Treatment)

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3 pages, 180 KiB

Open AccessEditorial

Vaccine Formulation for Infectious Diseases and Adjuvant Mechanisms of Action

by Heather L. Wilson, Azita Haddadi and George K. Mutwiri

Vaccines 2021, 9(6), 667; https://doi.org/10.3390/vaccines9060667 - 18 Jun 2021

Cited by 1 | Viewed by 1807

Abstract

The ultimate goal for vaccination is the generation of a safe and effective immune response that protects against diseases [...] Full article

(This article belongs to the Special Issue Vaccine Formulation for Infectious Diseases and Adjuvant Mechanisms of Action)

11 pages, 224 KiB

Open AccessArticle

Acceptance of COVID-19 Vaccine among the Healthcare Workers in the Eastern Cape, South Africa: A Cross Sectional Study

by Oladele Vincent Adeniyi, David Stead, Mandisa Singata-Madliki, Joanne Batting, Matthew Wright, Eloise Jelliman, Shareef Abrahams and Andrew Parrish

Vaccines 2021, 9(6), 666; https://doi.org/10.3390/vaccines9060666 - 18 Jun 2021

Cited by 50 | Viewed by 5372

Abstract

Background: This study assesses the perceptions and acceptance of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccination. It also examines its influencing factors among the healthcare workers (HCWs) in the Eastern Cape, South Africa. Methods: In this cross-sectional study performed in November and December [...] Read more.

Background: This study assesses the perceptions and acceptance of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccination. It also examines its influencing factors among the healthcare workers (HCWs) in the Eastern Cape, South Africa. Methods: In this cross-sectional study performed in November and December 2020, a total of 1308 HCWs from two large academic hospitals participated in the Eastern Cape Healthcare Workers Acquisition of SARS-CoV-2 (ECHAS) study. Validated measures of vaccine hesitancy were explored using a questionnaire. Logistic regression was used to identify the determinants of vaccine hesitancy. Results: The majority were nurses (45.2%), and at risk for unfavourable Covid-19 outcome, due to obesity (62.9%) and having direct contact with individuals confirmed to have Covid-19 (77.1%). The overall acceptance of SARS-CoV-2 vaccine was 90.1%, which differed significantly by level of education. Individuals with lower educational attainment (primary and secondary education) and those with prior vaccine refusal were less likely to accept the SARS-CoV-2 vaccine. However, positive perceptions about the SARS-CoV-2 vaccine were independently associated with vaccine acceptance. Conclusions: The high level of acceptance of SARS-CoV-2 vaccine is reassuring; however, HCWs with a lower level of education and those with prior vaccine refusal should be targeted for further engagements to address their concerns and fears. Full article

12 pages, 766 KiB

Open AccessArticle

COVID-19 Vaccine Hesitancy in a Representative Education Sector Population in Qatar

by Reem Al-Mulla, Marawan Abu-Madi, Qusai M. Talafha, Reema F. Tayyem and Atiyeh M. Abdallah

Vaccines 2021, 9(6), 665; https://doi.org/10.3390/vaccines9060665 - 18 Jun 2021

Cited by 40 | Viewed by 5701

Abstract

Even though vaccination programs have now started in earnest across the globe and in Qatar, vaccine hesitancy remains a barrier to effectively tackling the pandemic. Many factors influence willingness to take vaccines including safety, efficacy, and side effects. Given their proximity to research [...] Read more.

Even though vaccination programs have now started in earnest across the globe and in Qatar, vaccine hesitancy remains a barrier to effectively tackling the pandemic. Many factors influence willingness to take vaccines including safety, efficacy, and side effects. Given their proximity to research and education, university students and employees represent an interesting cohort in which to investigate vaccine hesitancy. The aim of this study was to assess the attitudes of Qatar University employees and students towards the COVID-19 vaccine. In total, 231 employees and 231 students participated in an online cross-sectional study in February 2021. Of the sample, 62.6% were willing to take a vaccine against COVID-19. Participants with or taking postgraduate degrees were more willing to take the vaccine compared to participants with or taking a diploma or bachelor’s degree (p < 0.001). Males had a higher rate of vaccine acceptance (p < 0.001). In the group that regarded flu vaccination as important, 13% were unwilling to take COVID-19 vaccine. There were no associations between willingness to vaccinate and vaccine/virus knowledge and social media use. Participants showed a high level of concern regarding vaccine side effects in themselves or their children. Two-thirds agreed or strongly agreed that they would take the vaccine if it was mandatory for international travel. Our participants were neutral to the origin of vaccine development. These findings, which represent data collected after the start of the national vaccination program, show that vaccine hesitancy persists in the Qatari population and that some groups, such as undergraduate students, could benefit from specific, targeted public health campaigns. Full article

(This article belongs to the Special Issue Vaccination and Public Health Version II: COVID-19 Vaccination)

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23 pages, 9306 KiB

Open AccessArticle

In Vitro Characterization of the Innate Immune Pathways Engaged by Live and Inactivated Tick-Borne Encephalitis Virus

by Aurora Signorazzi, Jeroen L. A. Pennings, Marilena P. Etna, Malou Noya, Eliana M. Coccia and Anke Huckriede

Vaccines 2021, 9(6), 664; https://doi.org/10.3390/vaccines9060664 - 17 Jun 2021

Cited by 3 | Viewed by 3081

Abstract

Tick-borne encephalitis virus (TBEV) infection can lead to inflammation of the central nervous system. The disease can be effectively prevented by whole inactivated virus vaccines. Here, we investigated the innate immune profile induced in vitro by the antigen component of the vaccines, inactivated [...] Read more.

Tick-borne encephalitis virus (TBEV) infection can lead to inflammation of the central nervous system. The disease can be effectively prevented by whole inactivated virus vaccines. Here, we investigated the innate immune profile induced in vitro by the antigen component of the vaccines, inactivated TBEV (I-TBEV), to gain insights into the mechanism of action of the TBE vaccine as compared to the live virus. To this end, we exposed human peripheral blood mononuclear cells (PBMCs) to inactivated and live TBEV and assessed cellular responses by RNA sequencing. Both inactivated and live TBEV significantly induced an interferon-dominated gene signature and an increased RIG-I-like receptor (RLR) expression. Using pathway-specific inhibitors, we assessed the involvement of pattern recognition receptors in the sensing of inactivated or live TBEV. Only RLR pathway inhibition significantly suppressed the downstream cascade induced by I-TBEV, while responses to the replicating virus were impacted by the inhibition of RIG-I-like, as well as Toll-like, receptors. Our results show that inactivated and live TBEV predominantly engaged an interferon response in our in vitro PBMC platform, and indicate RLRs as the main pattern recognition receptors involved in I-TBEV sensing. Full article

(This article belongs to the Special Issue Decoding Host and Microbial Communications in Infection and Vaccination)

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10 pages, 1316 KiB

Open AccessArticle

Immune Response to Vaccination against COVID-19 in Breastfeeding Health Workers

by Katarzyna Jakuszko, Katarzyna Kościelska-Kasprzak, Marcelina Żabińska, Dorota Bartoszek, Paweł Poznański, Dagna Rukasz, Renata Kłak, Barbara Królak-Olejnik and Magdalena Krajewska

Vaccines 2021, 9(6), 663; https://doi.org/10.3390/vaccines9060663 - 17 Jun 2021

Cited by 38 | Viewed by 19068

Abstract

Background: Initially, there were no data on the safety of COVID-19 vaccines in lactating women. The aim of our study was to evaluate the immune response to COVID-19 vaccinations in breastfeeding women. Methods: The study included 32 breastfeeding women who, regardless of the [...] Read more.

Background: Initially, there were no data on the safety of COVID-19 vaccines in lactating women. The aim of our study was to evaluate the immune response to COVID-19 vaccinations in breastfeeding women. Methods: The study included 32 breastfeeding women who, regardless of the study, had decided to be vaccinated. Maternal serum and breast milk samples were simultaneously collected on days 8 ± 1, 22 ± 2, 29 ± 3, and 43 ± 4 after the first dose of the vaccine. The immune response was assessed by determining the presence of anti-SARS-CoV-2 IgG and IgA. Results: The breast milk IgG level was detectable (6.50 ± 6.74, median 4.7, and maximum 34.2 BAU/mL) and highly correlated to serum IgG level (r_S 0.89; p < 0.001). The breast milk ratio of IgA to the cut-off value was higher in serum IgA-positive (4.18 ± 3.26, median 2.8, and maximum >10) than in serum IgA-negative women (0.56 ± 0.37, median 0.5, and maximum 1.6; p < 0.001). The highest concentrations of serum and breast milk antibodies were observed on day 29 ± 3 with a decrease on day 43 ± 4. Conclusion: The immune response to the vaccination against SARS-CoV-2 is strongest 7 ± 3 days after the second dose of the vaccine. Lactating mothers breastfeeding their children after vaccination against SARS-CoV-2 may transfer antibodies to their infant. Full article

(This article belongs to the Section COVID-19 Vaccines and Vaccination)

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10 pages, 241 KiB

Open AccessArticle

COVID-19 Vaccine Hesitancy and Its Associated Factors in Japan

by Ryo Okubo, Takashi Yoshioka, Satoko Ohfuji, Takahiro Matsuo and Takahiro Tabuchi

Vaccines 2021, 9(6), 662; https://doi.org/10.3390/vaccines9060662 - 17 Jun 2021

Cited by 103 | Viewed by 21989

Abstract

The vaccine confidence index in Japan is one of the lowest worldwide. This study aimed to examine the proportion of COVID-19 vaccine hesitancy in the Japanese population using a larger sample and more robust statistical methods than previously, and to identify factors associated [...] Read more.

The vaccine confidence index in Japan is one of the lowest worldwide. This study aimed to examine the proportion of COVID-19 vaccine hesitancy in the Japanese population using a larger sample and more robust statistical methods than previously, and to identify factors associated with vaccine hesitancy. We conducted a nationwide, cross-sectional Internet survey on 8–26 February 2021, and calculated the proportion and odds ratios for vaccine hesitancy. Among 23,142 responses analyzed, the proportion of COVID-19 vaccine hesitancy was 11.3% (10.9–11.7%). The proportion was higher among younger respondents and female respondents, and especially among younger female respondents (15.6%) compared with the lowest proportion among older male respondents (4.8%). The most cited reason for not getting vaccinated was concerns about adverse reactions in more than 70% of the respondents. The proportion of COVID-19 vaccine hesitancy in Japan was comparable to that in previous studies overseas, and the proportion among younger respondents was more than double that among older respondents. Factors associated with the hesitancy were female sex, living alone, low socioeconomic status, and presence of severe psychological distress, especially among older respondents. Thus, adequate measures should be taken to ensure that vaccines are delivered to people with these factors. Full article

(This article belongs to the Special Issue SARS-CoV-2 (COVID-19) Vaccination and Compliance/Hesitancy)

13 pages, 623 KiB

Open AccessArticle

Global Trends and Correlates of COVID-19 Vaccination Hesitancy: Findings from the iCARE Study

by Jovana Stojanovic, Vincent G. Boucher, Myriam Gagne, Samir Gupta, Keven Joyal-Desmarais, Stefania Paduano, Ala’ S. Aburub, Sherri N. Sheinfeld Gorin, Angelos P. Kassianos, Paula A. B. Ribeiro, Simon L. Bacon and Kim L. Lavoie

Vaccines 2021, 9(6), 661; https://doi.org/10.3390/vaccines9060661 - 17 Jun 2021

Cited by 55 | Viewed by 6931

Abstract

The success of large-scale COVID-19 vaccination campaigns is contingent upon people being willing to receive the vaccine. Our study explored COVID-19 vaccine hesitancy and its correlates in eight different countries around the globe. We analyzed convenience sample data collected between March 2020 and [...] Read more.

The success of large-scale COVID-19 vaccination campaigns is contingent upon people being willing to receive the vaccine. Our study explored COVID-19 vaccine hesitancy and its correlates in eight different countries around the globe. We analyzed convenience sample data collected between March 2020 and January 2021 as part of the iCARE cross-sectional study. Univariate and multivariate statistical analyses were conducted to explore the correlates of vaccine hesitancy. We included 32,028 participants from eight countries, and observed that 27% of the participants exhibited vaccine hesitancy, with increases over time. France reported the highest level of hesitancy (47.3%) and Brazil reported the lowest (9.6%). Women, younger individuals (≤29 years), people living in rural areas, and those with a lower perceived income were more likely to be hesitant. People who previously received an influenza vaccine were 70% less likely to report COVID-19 vaccine hesitancy. We observed that people reporting greater COVID-19 health concerns were less likely to be hesitant, whereas people with higher personal financial concerns were more likely to be hesitant. Our findings indicate that there is substantial vaccine hesitancy in several countries, with cross-national differences in the magnitude and direction of the trend. Vaccination communication initiatives should target hesitant individuals (women, younger adults, people with lower incomes and those living in rural areas), and should highlight the immediate health, social and economic benefits of vaccination across these settings. Country-level analyses are warranted to understand the complex psychological, socio-environmental, and cultural factors associated with vaccine hesitancy. Full article

(This article belongs to the Special Issue COVID-19 Vaccines: A Public Health Perspective)

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10 pages, 5352 KiB

Open AccessArticle

Development of a Macrophage-Based ADCC Assay

by Melissa B. Uccellini, Sadaf Aslam, Sean T. H. Liu, Fahmida Alam and Adolfo García-Sastre

Vaccines 2021, 9(6), 660; https://doi.org/10.3390/vaccines9060660 - 17 Jun 2021

Cited by 7 | Viewed by 3643

Abstract

Fc-dependent effector functions are an important determinant of the in vivo potency of therapeutic antibodies. Effector function is determined by the combination of FcRs bound by the antibody and the cell expressing the relevant FcRs, leading to antibody-dependent cellular cytotoxicity (ADCC). A number [...] Read more.

Fc-dependent effector functions are an important determinant of the in vivo potency of therapeutic antibodies. Effector function is determined by the combination of FcRs bound by the antibody and the cell expressing the relevant FcRs, leading to antibody-dependent cellular cytotoxicity (ADCC). A number of ADCC assays have been developed; however, they suffer from limitations in terms of throughput, reproducibility, and in vivo relevance. Existing assays measure NK cell-mediated ADCC activity; however, studies suggest that macrophages mediate the effector function of many antibodies in vivo. Here, we report the development of a macrophage-based ADCC assay that relies on luciferase expression in target cells as a measure of live cell number. In the presence of primary mouse macrophages and specific antibodies, loss of luciferase signal serves as a surrogate for ADCC-dependent killing. We show that the assay functions for a variety of mouse and human isotypes with a model antigen/antibody complex in agreement with the known effector function of the isotypes. We also use this assay to measure the activity of a number of influenza-specific antibodies and show that the assay correlates well with the known in vivo effector functions of these antibodies. Full article

(This article belongs to the Special Issue Immune Responses to Influenza Virus Antigens)

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7 pages, 241 KiB

Open AccessArticle

First Dose of the BNT162b2 mRNA COVID-19 Vaccine Reduces Symptom Duration and Viral Clearance in Healthcare Workers

by Luca Coppeta, Ottavia Balbi, Zaira Grattagliano, Grazia Genga Mina, Antonio Pietroiusti, Andrea Magrini, Matteo Bolcato and Marco Trabucco Aurilio

Vaccines 2021, 9(6), 659; https://doi.org/10.3390/vaccines9060659 - 17 Jun 2021

Cited by 17 | Viewed by 5174

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than one hundred million people since the beginning of the worldwide pandemic. In this study, data from a large hospital in central Italy was used to evaluate the impact of the first dose [...] Read more.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than one hundred million people since the beginning of the worldwide pandemic. In this study, data from a large hospital in central Italy was used to evaluate the impact of the first dose of the BNT162b2 mRNA vaccine on SARS-CoV-2 infections in terms of the prevalence of symptomatic cases, symptom duration, and viral clearance timing. All vaccinated Healthcare Workers (HCWs) with positive RT-PCR by nasopharyngeal (NP) swabs were divided into two cohorts (positive RT-PCR within day 12 and positive RT-PCR between day 13 and day 21 after first dose administration) and compared for the presence and duration of symptoms and the timing of viral clearance. The same variables were evaluated across HCWs with positive RT-PCR within 6 days after first dose administration and non-vaccinated HCWs with positive RT-PCR between 1 October 2020 and 28 February 2021. Eighteen HCWs tested positive on RT-PCR by NP swab from day 1 to day 12 after the 1st dose administration (incidence rate 6.2 × 10⁻⁴) and 5 HCWs from day 13 to day 21 (incidence rate 2.3 × 10⁻⁴). Symptom duration and viral clearance timing are significantly shorter in the cohort of HCWs with positive RT-PCR 12 days after the first dose of the BNT162b2 mRNA vaccine. The administration of the first dose proved effective in reducing presence, symptom duration, and viral clearance even in HCWs vaccinated for less than 6 days. These results could have implications on public health and post-exposure prophylaxis. Full article

(This article belongs to the Special Issue Phase IV Research in Vaccine Epidemiology: Immunogenicity, Effectiveness, and Safety)

21 pages, 26247 KiB

Open AccessArticle

Integrated Core Proteomics, Subtractive Proteomics, and Immunoinformatics Investigation to Unveil a Potential Multi-Epitope Vaccine against Schistosomiasis

by Abdur Rehman, Sajjad Ahmad, Farah Shahid, Aqel Albutti, Ameen S. S. Alwashmi, Mohammad Abdullah Aljasir, Naif Alhumeed, Muhammad Qasim, Usman Ali Ashfaq and Muhammad Tahir ul Qamar

Vaccines 2021, 9(6), 658; https://doi.org/10.3390/vaccines9060658 - 16 Jun 2021

Cited by 31 | Viewed by 4525

Abstract

Schistosomiasis is a parasitic infection that causes considerable morbidity and mortality in the world. Infections of parasitic blood flukes, known as schistosomes, cause the disease. No vaccine is available yet and thus there is a need to design an effective vaccine against schistosomiasis. [...] Read more.

Schistosomiasis is a parasitic infection that causes considerable morbidity and mortality in the world. Infections of parasitic blood flukes, known as schistosomes, cause the disease. No vaccine is available yet and thus there is a need to design an effective vaccine against schistosomiasis. Schistosoma japonicum, Schistosoma mansoni, and Schistosoma haematobium are the main pathogenic species that infect humans. In this research, core proteomics was combined with a subtractive proteomics pipeline to identify suitable antigenic proteins for the construction of a multi-epitope vaccine (MEV) against human-infecting Schistosoma species. The pipeline revealed two antigenic proteins—calcium binding and mycosubtilin synthase subunit C—as promising vaccine targets. T and B cell epitopes from the targeted proteins were predicted using multiple bioinformatics and immunoinformatics databases. Seven cytotoxic T cell lymphocytes (CTL), three helper T cell lymphocytes (HTL), and four linear B cell lymphocytes (LBL) epitopes were fused with a suitable adjuvant and linkers to design a 217 amino-acid-long MEV. The vaccine was coupled with a TLR-4 agonist (RS-09; Sequence: APPHALS) adjuvant to enhance the immune responses. The designed MEV was stable, highly antigenic, and non-allergenic to human use. Molecular docking, molecular dynamics (MD) simulations, and molecular mechanics/generalized Born surface area (MMGBSA) analysis were performed to study the binding affinity and molecular interactions of the MEV with human immune receptors (TLR2 and TLR4) and MHC molecules (MHC I and MHC II). The MEV expression capability was tested in an Escherichia coli (strain-K12) plasmid vector pET-28a(+). Findings of these computer assays proved the MEV as highly promising in establishing protective immunity against the pathogens; nevertheless, additional validation by in vivo and in vitro experiments is required to discuss its real immune-protective efficacy. Full article

(This article belongs to the Special Issue Genomic Medicine and Advances in Vaccine Technology and Development 2.0)

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16 pages, 1127 KiB

Open AccessReview

An Antigenic Thrift-Based Approach to Influenza Vaccine Design

by Jai S. Bolton, Hannah Klim, Judith Wellens, Matthew Edmans, Uri Obolski and Craig P. Thompson

Vaccines 2021, 9(6), 657; https://doi.org/10.3390/vaccines9060657 - 16 Jun 2021

Cited by 4 | Viewed by 4718

Abstract

The antigenic drift theory states that influenza evolves via the gradual accumulation of mutations, decreasing a host’s immune protection against previous strains. Influenza vaccines are designed accordingly, under the premise of antigenic drift. However, a paradox exists at the centre of influenza research. [...] Read more.

The antigenic drift theory states that influenza evolves via the gradual accumulation of mutations, decreasing a host’s immune protection against previous strains. Influenza vaccines are designed accordingly, under the premise of antigenic drift. However, a paradox exists at the centre of influenza research. If influenza evolved primarily through mutation in multiple epitopes, multiple influenza strains should co-circulate. Such a multitude of strains would render influenza vaccines quickly inefficacious. Instead, a single or limited number of strains dominate circulation each influenza season. Unless additional constraints are placed on the evolution of influenza, antigenic drift does not adequately explain these observations. Here, we explore the constraints placed on antigenic drift and a competing theory of influenza evolution – antigenic thrift. In contrast to antigenic drift, antigenic thrift states that immune selection targets epitopes of limited variability, which constrain the variability of the virus. We explain the implications of antigenic drift and antigenic thrift and explore their current and potential uses in the context of influenza vaccine design. Full article

(This article belongs to the Special Issue Immune Responses to Influenza Virus Antigens)

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14 pages, 998 KiB

Open AccessArticle

Antivaccine Movement and COVID-19 Negationism: A Content Analysis of Spanish-Written Messages on Twitter

by Ivan Herrera-Peco, Beatriz Jiménez-Gómez, Carlos Santiago Romero Magdalena, Juan José Deudero, María García-Puente, Elvira Benítez De Gracia and Carlos Ruiz Núñez

Vaccines 2021, 9(6), 656; https://doi.org/10.3390/vaccines9060656 - 15 Jun 2021

Cited by 37 | Viewed by 5927

Abstract

During the COVID-19 pandemic, different conspiracies have risen, with the most dangerous being those focusing on vaccines. Today, there exists a social media movement focused on destroying the credibility of vaccines and trying to convince people to ignore the advice of governments and [...] Read more.

During the COVID-19 pandemic, different conspiracies have risen, with the most dangerous being those focusing on vaccines. Today, there exists a social media movement focused on destroying the credibility of vaccines and trying to convince people to ignore the advice of governments and health organizations on vaccination. Our aim was to analyze a COVID-19 antivaccination message campaign on Twitter that uses Spanish as the main language, to find the key elements in their communication strategy. Twitter data were retrieved from 14 to 28 December using NodeXL software. We analyzed tweets in Spanish, focusing on influential users, most influential tweets, and content analysis of tweets. The results revealed ordinary citizens who ‘offer the truth’ as the most important profile in this network. The content analysis showed antivaccine tweets (31.05%) as the most frequent. The analysis of anti-COVID19 tweets showed that attacks against vaccine safety were the most important (79.87%) but we detected a new kind of message presenting the vaccine as a means of manipulating the human genetic code (8.1%). We concluded that the antivaccine movement and its tenets have great influence in the COVID-19 negationist movement. We observed a new topic in COVID-19 vaccine hoaxes that must be considered in our fight against misinformation. Full article

(This article belongs to the Special Issue Vaccines: Uptake and Equity in Times of the COVID-19 Pandemic)

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12 pages, 695 KiB

Open AccessReview

Natural Killer Cell Responses during Human γ-Herpesvirus Infections

by Christian Münz

Vaccines 2021, 9(6), 655; https://doi.org/10.3390/vaccines9060655 - 15 Jun 2021

Cited by 7 | Viewed by 2870

Abstract

Herpesviruses are main sculptors of natural killer (NK) cell repertoires. While the β-herpesvirus human cytomegalovirus (CMV) drives the accumulation of adaptive NKG2C-positive NK cells, the human γ-herpesvirus Epstein–Barr virus (EBV) expands early differentiated NKG2A-positive NK cells. While adaptive NK cells support adaptive immunity [...] Read more.

Herpesviruses are main sculptors of natural killer (NK) cell repertoires. While the β-herpesvirus human cytomegalovirus (CMV) drives the accumulation of adaptive NKG2C-positive NK cells, the human γ-herpesvirus Epstein–Barr virus (EBV) expands early differentiated NKG2A-positive NK cells. While adaptive NK cells support adaptive immunity by antibody-dependent cellular cytotoxicity, NKG2A-positive NK cells seem to preferentially target lytic EBV replicating B cells. The importance of this restriction of EBV replication during γ-herpesvirus pathogenesis will be discussed. Furthermore, the modification of EBV-driven NK cell expansion by coinfections, including by the other human γ-herpesvirus Kaposi sarcoma-associated herpesvirus (KSHV), will be summarized. Full article

(This article belongs to the Special Issue Role of Nk Cells and Non-nk Ilcs in Disease Progression and Their Application as Targets for Immune Interventions)

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13 pages, 2425 KiB

Open AccessArticle

COVID-19 Vaccine Acceptance, Hesitancy, and Resistancy among University Students in France

by Marie Pierre Tavolacci, Pierre Dechelotte and Joel Ladner

Vaccines 2021, 9(6), 654; https://doi.org/10.3390/vaccines9060654 - 15 Jun 2021

Cited by 83 | Viewed by 10903

Abstract

The objectives were to explore, among university students, the level of COVID-19 vaccine acceptance, hesitancy, and resistancy and to determine the motivations and barriers, and the reasons that may change student vaccination decision making. An online observational cross-sectional study was conducted among students [...] Read more.

The objectives were to explore, among university students, the level of COVID-19 vaccine acceptance, hesitancy, and resistancy and to determine the motivations and barriers, and the reasons that may change student vaccination decision making. An online observational cross-sectional study was conducted among students of a French university in January 2021 with questions about the intention to be vaccinated against COVID-19, the motivations and the barriers. The convenience sample included 3089 students, with a mean of age of 20.3 (SD = 1.9). To the question on the intention to vaccinate against the COVID-19, 58.0% of students reported that they would choose to have a vaccination, 17.0% reported that they would not and 25.0% were not sure. The main motivations for vaccine acceptance were “I don′t want to transmit COVID-19 to others”, the main barriers for vaccine resistance or hesitancy were “I prefer to wait until I have more experience with these new vaccines”. Age, female gender, being in first three years of study, studied sciences courses and neither sciences nor healthcare courses of study were significantly associated with a higher risk of vaccine hesitancy or resistancy. Self-estimated knowledge of conventional vaccines and COVID-19 vaccines, and confidence in efficiency and safety of conventional vaccination were associated with a lower risk of vaccine hesitancy or resistancy. It is relevant to disseminate evidence-based interventions to promote COVID-19 vaccine acceptability for college students, especially for the students in neither sciences nor healthcare courses of study, as college students will soon be eligible to receive a COVID-19 vaccine. Full article

(This article belongs to the Section COVID-19 Vaccines and Vaccination)

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10 pages, 841 KiB

Open AccessArticle

Differential Demographic and Clinical Characteristics between MMR Vaccinated and Unvaccinated Children in South Korea: A Nationwide Study

by Dongwon Yoon, Juhwan Kim and Juyoung Shin

Vaccines 2021, 9(6), 653; https://doi.org/10.3390/vaccines9060653 - 15 Jun 2021

Viewed by 2485

Abstract

In the context of recent measles outbreaks, substantial factors associated with measles-mumps-rubella (MMR) unvaccination need to be clarified. This study aimed to identify differential demographic and clinical characteristics between MMR vaccinated and unvaccinated groups. We used a large-linked database to identify children born [...] Read more.

In the context of recent measles outbreaks, substantial factors associated with measles-mumps-rubella (MMR) unvaccination need to be clarified. This study aimed to identify differential demographic and clinical characteristics between MMR vaccinated and unvaccinated groups. We used a large-linked database to identify children born between 2008 and 2016 by combining data from the Korea Immunization Registry Information System and National Health Information database. The MMR vaccination status was ascertained up to the age of 2 to define MMR vaccinated and unvaccinated groups. We conducted a multivariate logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs) to identify factors associated with MMR unvaccination. Of 3,973,253 children, 75,674 (1.9%) did not receive the MMR vaccine. Compared with the MMR vaccinated group, the underutilization of healthcare resources was more notable in the MMR unvaccinated group (number of outpatient visits (5.73 ± 12.1 vs. 25.8 ± 17.06); days hospitalized (1.69 ± 14.5 vs. 2.32 ± 6.90)). Children were less likely to receive the MMR vaccine if they were born with congenital anomaly (OR 2.12; 95% CI 1.90–2.36), were never admitted to an intensive care unit (1.88; 1.78–1.98), or never visited an emergency room (3.57; 3.53–3.72). There were substantial factors associated with MMR unvaccination, underscoring a need to optimize targeted interventions tailored to the subset of children in South Korea. Full article

(This article belongs to the Special Issue Pharmacoepidemiology in Vaccine: Generating the Real-World Data to Promote Vaccine Safety and Uptake)

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Vaccines, Volume 9, Issue 6 (June 2021) – 147 articles

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