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Vaccines
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COVID-19: Epidemiology and Transmission
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COVID-19: Epidemiology and Transmission

A special issue of Vaccines (ISSN 2076-393X). This special issue belongs to the section "Epidemiology".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 42462

Special Issue Editors

Prof. Dr. Xiaohua Zhou

E-Mail Website
Guest Editor
1. PKU Endowed Chair Professor, Beijing International Center for Mathematical Research, Peking University, Beijing, China
2. Chair, Department of Biostatistics, School of Public Health, Peking University, Beijing, China
Interests: statistical methods for diagnostic medicine; causal inference; mathematical modeling of infectious disease
Dr. Chong You

E-Mail Website
Guest Editor
Beijing International Center for Mathematical Research, Peking University, Beijing, China
Interests: variational Bayes; model selection; mathematical modeling of infectious disease

Special Issue Information

Dear Colleagues,

The current outbreak of coronavirus disease 2019 (COVID-19) has been going on for nearly two years and is deemed as a once-in-a-century health crisis. Vaccination is considered the most promising way to end the COVID-19 pandemic while restoring social activities.

A collective global effort has been invested into the vaccination against SARS-CoV-2. As of December 2021, eight vaccines have been approved for use by WHO whilst over 300 vaccine candidates are under (pre-)clinical development. As a result, vaccination campaigns have been carried out in many countries while the coverage varies greatly. It can be as high as  90% (double vaccinated) in United Arab Emirates or 1.2% in Yemen. While the vaccination has been proven to significantly reduce the development of severe symptoms after infection from the original and certain mutated strain of the virus, the emergence of new mutated strains would potentially disrupt such protection, for example, Omicron.

In this Special Issue, all studies and reviews that can shed new light on the mechanisms, storage, efficiency, dosage specification, and side effects of COVID-19 vaccines, or those that can elucidate the vaccination strategies in the context of limited vaccination capacity and the effect of vaccines in the transmission, are all welcome.

Prof. Dr. Xiaohua Zhou
Dr. Chong You
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Vaccines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • COVID-19
  • vaccine
  • immunization
  • efficacy evaluation
  • immune evasion
  • vaccine prioritization
  • containment measures
  • herd immunity

Published Papers (22 papers)

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Research

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16 pages, 3413 KiB  
Article
Population-Level Immunity for Transient Suppression of COVID-19 Waves in Japan from April 2021 to September 2022
by Sachiko Kodera, Haruto Ueta, Tatsuo Unemi, Taisuke Nakata and Akimasa Hirata
Vaccines 2023, 11(9), 1457; https://doi.org/10.3390/vaccines11091457 - 04 Sep 2023
Cited by 1 | Viewed by 1121
Abstract
Multiple COVID-19 waves have been observed worldwide, with varying numbers of positive cases. Population-level immunity can partly explain a transient suppression of epidemic waves, including immunity acquired after vaccination strategies. In this study, we aimed to estimate population-level immunity in 47 Japanese prefectures [...] Read more.
Multiple COVID-19 waves have been observed worldwide, with varying numbers of positive cases. Population-level immunity can partly explain a transient suppression of epidemic waves, including immunity acquired after vaccination strategies. In this study, we aimed to estimate population-level immunity in 47 Japanese prefectures during the three waves from April 2021 to September 2022. For each wave, characterized by the predominant variants, namely, Delta, Omicron, and BA.5, the estimated rates of population-level immunity in the 10–64-years age group, wherein the most positive cases were observed, were 20%, 35%, and 45%, respectively. The number of infected cases in the BA.5 wave was inversely associated with the vaccination rates for the second and third injections. We employed machine learning to replicate positive cases in three Japanese prefectures to validate the reliability of our model for population-level immunity. Using interpolation based on machine learning, we estimated the impact of behavioral factors and vaccination on the fifth wave of new positive cases that occurred during the Tokyo 2020 Olympic Games. Our computational results highlighted the critical role of population-level immunity, such as vaccination, in infection suppression. These findings underscore the importance of estimating and monitoring population-level immunity to predict the number of infected cases in future waves. Such estimations that combine numerical derivation and machine learning are of utmost significance for effective management of medical resources, including the vaccination strategy. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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15 pages, 3847 KiB  
Article
VLP-ELISA for the Detection of IgG Antibodies against Spike, Envelope, and Membrane Antigens of SARS-CoV-2 in Indian Population
by Dilip Kumar, Sourav Singha Roy, Ruchir Rastogi, Kajal Arora, Avinash Undale, Reeshu Gupta, Nupur Mehrotra Arora and Prabuddha K. Kundu
Vaccines 2023, 11(4), 743; https://doi.org/10.3390/vaccines11040743 - 27 Mar 2023
Cited by 1 | Viewed by 2206
Abstract
Background: Serological methods to conduct epidemiological survey are often directed only against the spike protein. To overcome this limitation, we have designed PRAK-03202, a virus-like particle (VLP), by inserting three antigens (Spike, envelope and membrane) of SARS-CoV-2 into a highly characterized S. cerevisiae [...] Read more.
Background: Serological methods to conduct epidemiological survey are often directed only against the spike protein. To overcome this limitation, we have designed PRAK-03202, a virus-like particle (VLP), by inserting three antigens (Spike, envelope and membrane) of SARS-CoV-2 into a highly characterized S. cerevisiae-based D-Crypt™ platform. Methods: Dot blot analysis was performed to confirm the presence of S, E, and M proteins in PRAK-03202. The number of particles in PRAK-03202 was measured using nanoparticle tracking analysis (NTA). The sensitivity of VLP-ELISA was evaluated in 100 COVID positive. PRAK-03202 was produced at a 5 L scale using fed-batch fermentation. Results: Dot blot confirmed the presence of S, E, and M proteins in PRAK-03202. The number of particles in PRAK-03202 was 1.21 × 109 mL−1. In samples collected >14 days after symptom onset, the sensitivity, specificity, and accuracy of VLP-ELISA were 96%. We did not observe any significant differences in sensitivity, specificity, and accuracy when post-COVID-19 samples were used as negative controls compared to pre-COVID-samples. At a scale of 5 L, the total yield of PRAK-03202 was 100–120 mg/L. Conclusion: In conclusion, we have successfully developed an in-house VLP-ELISA to detect IgG antibodies against three antigens of SARS-CoV-2 as a simple and affordable alternative test. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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15 pages, 3140 KiB  
Article
COVID-19 in a Pre-Omicron Era: A Cross-Sectional Immuno-Epidemical and Genomic Evaluation
by Jorge Pamplona Pagnossa, Sarah de Oliveira Rodrigues, Gabriel Ferrari de Oliveira, Mohd Adnan, Maryam Saud Aljaid, Isabela Bacelar de Assis, Alex Sandro Gomes Lima, Mitesh Patel, Hanan A. Ogaly and Gaber El-Saber Batiha
Vaccines 2023, 11(2), 272; https://doi.org/10.3390/vaccines11020272 - 27 Jan 2023
Cited by 1 | Viewed by 1446
Abstract
The seventh human coronavirus was discovered and reported primarily in Wuhan, China. After intense seasons with repercussions in all areas of humanity, the pandemic demonstrates a new perspective. In Brazil, the pandemic concept had impacts in vast areas, including healthcare hospitals. This present [...] Read more.
The seventh human coronavirus was discovered and reported primarily in Wuhan, China. After intense seasons with repercussions in all areas of humanity, the pandemic demonstrates a new perspective. In Brazil, the pandemic concept had impacts in vast areas, including healthcare hospitals. This present study aims to describe and synthesize data from a determined period from the year 2021 that correlate the symptoms of passive and/or active patients for COVID-19 and their respective results of IgG/IgM serological tests in hospitals in the city of Cruzeiro, São Paulo, Brazil. The form had been applied to 333 people and obtained conclusive results and several symptoms were presented; in addition, asymptomatic cases were also analyzed and directed in the genomic study of variants of concern, as well as vaccination data in the study region. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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18 pages, 316 KiB  
Article
The Relationship between Daily Behavior Changes and Vaccine Attitudes at the Early Stage of the COVID-19 Pandemic among Japanese People from Different Demographics: A Retrospective and Exploratory Examination Using a Free-Response Survey
by Mariko Kikutani, Mie Matsui and Yuta Takiguchi
Vaccines 2023, 11(1), 192; https://doi.org/10.3390/vaccines11010192 - 16 Jan 2023
Viewed by 1448
Abstract
This study investigated how daily behaviors of Japanese people changed during the early stages of the COVID-19 pandemic and whether the change was mediated by demographics. It also examined whether the magnitude of behavior change in a demographic group is related to their [...] Read more.
This study investigated how daily behaviors of Japanese people changed during the early stages of the COVID-19 pandemic and whether the change was mediated by demographics. It also examined whether the magnitude of behavior change in a demographic group is related to their attitudes towards the COVID-19 vaccine. 301 Japanese responded to an online survey in February 2021, in which they first wrote some activities they frequently performed before the virus outbreak and then wrote about activities in their current life. The number of gathered answers were 1858 for ‘before’ and 1668 for ‘after’, and they were grouped into 19 behavior categories. Overall, behaviors such as traveling, eating out, and shopping were much less frequently described in the ‘after’ condition; while housework, food delivery, and pandemic prevention were mentioned more. However, the change pattern was significantly influenced by demographics of age, gender, having children or not, and household income. Especially women, younger generations, and people without children showed the greatest extent of behavior change compared with the other demographic cohorts. These groups were reported to be vaccine-hesitant in the literature. This study suggests that individuals with hesitant attitudes towards vaccines are more willing to change their behaviors to control viral transmission. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
10 pages, 614 KiB  
Article
Mortality and Associated Factors in Patients with COVID-19: Cross-Sectional Study
by Vergílio Pereira Carvalho, João Paulo Jordão Pontes, Demócrito Ribeiro de Brito Neto, Celso Eduardo Rezende Borges, Gisele Ribeiro Londe Campos, Hugo Leonardo Shigenaga Ribeiro and Waldemar Naves do Amaral
Vaccines 2023, 11(1), 71; https://doi.org/10.3390/vaccines11010071 - 28 Dec 2022
Cited by 3 | Viewed by 1497
Abstract
The novel virus severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is highly virulent and causes coronavirus disease 2019 (COVID-19), resulting in high morbidity and mortality mainly associated with pulmonary complications. Because this virus is highly transmissible, it was quickly spread globally, resulting in [...] Read more.
The novel virus severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) is highly virulent and causes coronavirus disease 2019 (COVID-19), resulting in high morbidity and mortality mainly associated with pulmonary complications. Because this virus is highly transmissible, it was quickly spread globally, resulting in COVID-19 being declared as a pandemic. This study aimed to analyze the prevalence of mortality and the factors related to mortality due to COVID-19 in patients with severe acute respiratory syndrome (SARS) at a university hospital in the Central—West region of Brazil. This retrospective cross-sectional study was based on an analysis of the medical records of patients with SARS aged >18 years and admitted to an intensive care unit due to COVID-19 with the requirement of invasive mechanical ventilation. Hospital death was considered as an outcome variable in this study. Moreover, demographic and lifestyle-related variables as well as the therapeutic measures used during the hospital stay were recorded and correlated with the death outcome. After excluding 188 medical records, 397 were analyzed. Most of the participants were men (59.7%), and the mortality rate in patients with SARS due to COVID-19 was 46.1%. Multiple regression analysis indicated that the independent factors associated with mortality in patients with SARS due to COVID-19 were the age of >60 years (p < 0.001) and the use of azithromycin (p = 0.012). Protective factors for mortality were considered as not having the following diseases: hyperthyroidism, asthma, hepatic inheritance, and not being a smoker. The mortality rate in patients with SARS due to COVID-19 was associated with older age and the use of azithromycin. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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12 pages, 1358 KiB  
Article
The Transmission Dynamics of a Compartmental Epidemic Model for COVID-19 with the Asymptomatic Population via Closed-Form Solutions
by Rehana Naz and Mariano Torrisi
Vaccines 2022, 10(12), 2162; https://doi.org/10.3390/vaccines10122162 - 16 Dec 2022
Cited by 1 | Viewed by 1130
Abstract
Unlike previous viral diseases, COVID-19 has an “asymptomatic” group that has no symptoms but can still spread the disease to others at the same rate as symptomatic patients who are infected. In the literature, the mass action or standard incidence rates are considered [...] Read more.
Unlike previous viral diseases, COVID-19 has an “asymptomatic” group that has no symptoms but can still spread the disease to others at the same rate as symptomatic patients who are infected. In the literature, the mass action or standard incidence rates are considered for compartmental models with asymptomatic compartment for studying the transmission dynamics of COVID-19, but the quarantined adjusted incidence rate is not. To bridge this gap, we developed a Susceptible Asymptomatic Infectious Quarantined (SAIQ) model with a Quarantine-Adjusted (QA) incidence to investigate the emergence and containment of COVID-19. COVID-19 models are investigated using various methods, but only a few studies take into account closed-form solutions. The knowledge of closed-form solutions simplifies the construction of the various epidemic indicators that describe the epidemic phenomenon and makes the sensitivity analysis to variations in the data under consideration possible. The closed-form solutions of the systems of four nonlinear first-order ordinary differential equations (ODEs) are established. The Epidemic Peak (EP), Force of Infection (FOI) and Rate of Infection (ROI) are the important indicators for the control and prevention of disease. We examined these indicators using closed-form solutions and particular parameter values. Different disease control scenarios are thoroughly examined. The four scenarios to analyze COVID-19 propagation and containment are (i) lockdown, (ii) quarantine and other preventative measures, (iii) stabilizing the basic reproduction rate to a level where the pandemic can be contained and (iv) containing the epidemic through an appropriate combination of lockdown, quarantine and other preventative measures. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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13 pages, 1199 KiB  
Article
COVID-19 and Pulmonary Embolism Outcomes among Hospitalized Patients in the United States: A Propensity-Matched Analysis of National Inpatient Sample
by Adeel Nasrullah, Karthik Gangu, Nichole B. Shumway, Harmon R. Cannon, Ishan Garg, Hina Shuja, Aniesh Bobba, Prabal Chourasia, Abu Baker Sheikh and Rahul Shekhar
Vaccines 2022, 10(12), 2104; https://doi.org/10.3390/vaccines10122104 - 08 Dec 2022
Cited by 5 | Viewed by 1747
Abstract
Venous thromboembolism, in particular, pulmonary embolism (PE), is a significant contributor to the morbidity and mortality associated with COVID-19. In this study, we utilized the National Inpatient Sample (NIS) database 2020 to evaluate and compare clinical outcomes in patients with COVID-19 with and [...] Read more.
Venous thromboembolism, in particular, pulmonary embolism (PE), is a significant contributor to the morbidity and mortality associated with COVID-19. In this study, we utilized the National Inpatient Sample (NIS) database 2020 to evaluate and compare clinical outcomes in patients with COVID-19 with and without PE. Our sample includes 1,659,040 patients hospitalized with COVID-19 pneumonia between January 2020 and December 2020. We performed propensity-matched analysis for patient characteristics and in-hospital outcomes, including the patient’s age, race, sex, insurance status, median income, length of stay, mortality, hospitalization cost, comorbidities, mechanical ventilation, and vasopressor support. Patients with COVID-19 with PE had a higher need for mechanical ventilation (25.7% vs. 15.6%, adjusted odds ratio 1.4, 95% CI 1.4–1.5, p < 0.001), the vasopressor requirement (5.4% vs. 2.6%, adjusted OR 1.6, 95% CI 1.4–1.8, p < 0.001), longer hospital stays (10.8 vs. 7.9 days, p < 0.001), and overall higher in-hospital mortality (19.1 vs. 13.9%, adjusted OR of 1.3, 95% CI 1.1–1.5, p < 0.001). This study highlights the need for more aggressive management of PE in COVID-19-positive patients with the aim to improve early diagnosis and treatment to reduce morbidity, mortality, and healthcare costs seen in the synchronous COVID-19 and PE-positive patients. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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12 pages, 1690 KiB  
Article
Waning of SARS-CoV-2 Seropositivity among Healthy Young Adults over Seven Months
by C. Suzanne Lea, Kristina Simeonsson, Aaron M. Kipp, Charleen McNeill, Lisa Wilcox, William Irish, Hannah Morris, Omar M. Diaz, John T. Fallon and Rachel L. Roper
Vaccines 2022, 10(9), 1532; https://doi.org/10.3390/vaccines10091532 - 15 Sep 2022
Cited by 5 | Viewed by 1826
Abstract
Background: We conducted a longitudinal study to estimate immunity produced in response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among university students over seven months. Methods: All participants were attending a public university and resided in Pitt County, North Carolina. University [...] Read more.
Background: We conducted a longitudinal study to estimate immunity produced in response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among university students over seven months. Methods: All participants were attending a public university and resided in Pitt County, North Carolina. University students enrolled weekly for 10 weeks between 26 August 2020 and 28 October 2020, resulting in 136 young adults completing at least one study visit by 17 November 2020. Enrolled students completed an online survey and nasal swab collection at two-week intervals and monthly blood collection between 26 August 2020 and 31 March 2021. Results: Amongst 695 serum samples tested during follow-up, the prevalence of a positive result for anti-nucleocapsid antibodies (N-IgG) was 9.78%. In 22 students with more than one positive N-IgG serum sample, 68.1% of the group lost persistence of N-IgG below the positive threshold over 140 days. Anti-spike IgG antibodies were significantly higher among 11 vaccinated compared to 10 unvaccinated. Conclusions: In healthy young adults, N-IgG wanes below the detectable threshold within five months. S-IgG titer remained consistently elevated months after infection, and significantly increased after vaccination. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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8 pages, 227 KiB  
Article
The Impact of the Patras Carnival on the Course of the COVID-19 Pandemic and the Outbreak of Influenza A: A Multicenter Cross-Sectional Study
by Christos Sotiropoulos, Vasileios Loulelis, Anna Mastorakou, Eleni Adamopoulou, Theoharis Kortesas, Aimilia Dimitropoulou, Eleni Blika, Ioanna Papadimitriou-Olivgeri and Ilona Binenbaum
Vaccines 2022, 10(9), 1484; https://doi.org/10.3390/vaccines10091484 - 06 Sep 2022
Viewed by 1377
Abstract
Background: We investigated the impact of the indoor mass gathering of young people during the Patras Carnival in Greece on the course of the COVID-19 pandemic and the influenza A epidemic. Materials and Methods: For influenza A, we tested 331 subjects with high [...] Read more.
Background: We investigated the impact of the indoor mass gathering of young people during the Patras Carnival in Greece on the course of the COVID-19 pandemic and the influenza A epidemic. Materials and Methods: For influenza A, we tested 331 subjects with high fever (>38 °C), who arrived at five separate private laboratories over a two-week period after the carnival, via rapid test. One hundred and eighty-eight of them were young adults (17–35 years old), all unvaccinated against influenza A but all immunized against SARS-CoV-2, either through vaccination or previous infection. For the SARS-CoV-2 pandemic, we tested 2062 subjects at two time periods, two weeks before and two weeks after the carnival, also via rapid test. Additionally, we examined 42 samples positive for influenza A and 51 samples positive for SARS-CoV-2 for the possibility of co-infection via molecular testing (i.e., RT-PCR). Results: 177/331 (53.5%) subjects tested positive for influenza A, and 109/177 (61.6%) of the positive subjects were young adults, and 93/109 (85.3%) of these subjects were tested in the first week after the carnival. Additionally, 42 samples of those subjects were molecularly tested, and 5 were found negative for influenza A but positive for SARS-CoV-2. Regarding the SARS-CoV-2 pandemic, the increase in the positivity index for young adults between the pre-carnival and post-carnival periods was moderate. Conclusions: Our study indicates that the indoor mass gathering of young people during the carnival contributed to the outbreak of an influenza A epidemic and had a moderate but not statistically significant impact on the course of the SARS-CoV-2 pandemic, corroborating the crucial role of vaccination against the epidemic’s waves. It also showed the need for the use of high-quality rapid tests for their management. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
12 pages, 298 KiB  
Article
High Seroprevalence of SARS-CoV-2 IgG and RNA among Asymptomatic Blood Donors in Makkah Region, Saudi Arabia
by Kamal H. Alzabeedi, Raafat T. M. Makhlof, Rowaida A. Bakri, Ashraf A. Ewis, Heba W. Alhamdi, Turki M. A. Habeebullah, Asim A. Khogeer, Eman A. A. Mulla, Safiah A. M. Roshan, Fadel H. Qabbani, Fayez H. Hafez, Rehab G. Alqurashi, Muhammad O. Babalghaith, Ahmad A. Ghouth, Mohammed H. Alhazmi, Othman M. Fallatah, Saeed A. Badahdah, Duaa I. A. Endergiri, Boshra M. Albarakati and Sayed F. Abdelwahab
Vaccines 2022, 10(8), 1279; https://doi.org/10.3390/vaccines10081279 - 08 Aug 2022
Cited by 1 | Viewed by 1859
Abstract
The gold-standard approach for diagnosing and confirming Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) infection is reverse transcription-polymerase chain reaction (RT-PCR). This method, however, is inefficient in detecting previous or dormant viral infections. The presence of antigen-specific antibodies is the fingerprint and cardinal [...] Read more.
The gold-standard approach for diagnosing and confirming Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) infection is reverse transcription-polymerase chain reaction (RT-PCR). This method, however, is inefficient in detecting previous or dormant viral infections. The presence of antigen-specific antibodies is the fingerprint and cardinal sign for diagnosis and determination of exposure to infectious agents including Corona virus disease-2019 (COVID-19). This cross-sectional study examined the presence of SARS-CoV-2 spike-specific immunoglobulin G (IgG) among asymptomatic blood donors in Makkah region. A total of 4368 asymptomatic blood donors were enrolled. They were screened for spike-specific IgG using ELISA and COVID-19 RNA by real-time PCR. COVID-19 IgG was detected among 2248 subjects (51.5%) while COVID-19-RNA was detected among 473 (10.8%) subjects. The IgG frequency was significantly higher among males and non-Saudi residents (p < 0.001 each) with no significant variation in IgG positivity among blood donors with different blood groups. In addition, COVID-19 RNA frequency was significantly higher among donors below 40-years old (p = 0.047, χ2 = 3.95), and non-Saudi residents (p = 0.001, χ2 = 304.5). The COVID-19 IgG levels were significantly higher among the RNA-positive donors (p = 001), and non-Saudi residents (p = 0.041), with no variations with age or blood group (p > 0.05). This study reveals a very high prevalence of COVID-19 IgG and RNA among asymptomatic blood donors in Makkah, Saudi Arabia indicating a high exposure rate of the general population to COVID-19; particularly foreign residents. It sheds light on the spread on COVID-19 among apparently healthy individuals at the beginning of the pandemic and could help in designing various control measures to minimize viral spread. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
15 pages, 1486 KiB  
Article
Self-Reported SARS-CoV-2 Vaccination Is Consistent with Electronic Health Record Data among the COVID-19 Community Research Partnership
by Ashley H. Tjaden, Lida M. Fette, Sharon L. Edelstein, Michael Gibbs, Amy N. Hinkelman, Michael Runyon, Roberto P. Santos, William S. Weintraub, Joshua Yukich, Diane Uschner and the COVID-19 Community Research Partnership Study Group
Vaccines 2022, 10(7), 1016; https://doi.org/10.3390/vaccines10071016 - 24 Jun 2022
Cited by 10 | Viewed by 1720
Abstract
Introduction: Observational studies of SARS-CoV-2 vaccine effectiveness depend on accurate ascertainment of vaccination receipt, date, and product type. Self-reported vaccine data may be more readily available to and less expensive for researchers than assessing medical records. Methods: We surveyed adult participants [...] Read more.
Introduction: Observational studies of SARS-CoV-2 vaccine effectiveness depend on accurate ascertainment of vaccination receipt, date, and product type. Self-reported vaccine data may be more readily available to and less expensive for researchers than assessing medical records. Methods: We surveyed adult participants in the COVID-19 Community Research Partnership who had an authenticated Electronic Health Record (EHR) (N = 41,484) concerning receipt of SARS-CoV-2 vaccination using a daily survey beginning in December 2020 and a supplemental survey in September–October 2021. We compared self-reported information to that available in the EHR for the following data points: vaccine brand, date of first dose, and number of doses using rates of agreement and Bland–Altman plots for visual assessment. Self-reported data was available immediately following vaccination (in the daily survey) and at a delayed interval (in a secondary supplemental survey). Results: For the date of first vaccine dose, self-reported “immediate” recall was within ±7 days of the date reported in the “delayed” survey for 87.9% of participants. Among the 19.6% of participants with evidence of vaccination in their EHR, 95% self-reported vaccination in one of the two surveys. Self-reported dates were within ±7 days of documented EHR vaccination for 97.6% of the “immediate” surveys and 92.0% of the “delayed” surveys. Self-reported vaccine product details matched those in the EHR for over 98% of participants for both “immediate” and “delayed” surveys. Conclusions: Self-reported dates and product details for COVID-19 vaccination can be a good surrogate when medical records are unavailable in large observational studies. A secondary confirmation of dates for a subset of participants with EHR data will provide internal validity. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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10 pages, 456 KiB  
Article
Determinants of SARS-CoV-2 Infection in the Older Adult Population: Data from the LOST in Lombardia Study
by Giansanto Mosconi, Chiara Stival, Alessandra Lugo, Carlo Signorelli, Andrea Amerio, Luca Cavalieri d’Oro, Licia Iacoviello, David Stuckler, Alberto Zucchi, Anna Odone, Silvano Gallus and the LOST in Lombardia Project Investigators
Vaccines 2022, 10(7), 989; https://doi.org/10.3390/vaccines10070989 - 22 Jun 2022
Cited by 4 | Viewed by 1715
Abstract
Most COVID-19 fatalities have occurred among older adults; however, evidence regarding the determinants of SARS-CoV-2 infection in this population is limited. Telephone interviews were conducted in November 2020 with a representative sample of 4400 Italians aged ≥65 years from the Lombardy region. We [...] Read more.
Most COVID-19 fatalities have occurred among older adults; however, evidence regarding the determinants of SARS-CoV-2 infection in this population is limited. Telephone interviews were conducted in November 2020 with a representative sample of 4400 Italians aged ≥65 years from the Lombardy region. We determined the prevalence of a history of SARS-CoV-2 infection. Through unconditional multiple logistic regression models, we estimated the odds ratios (ORs) of infection and the corresponding 95% confidence intervals (CIs). We further evaluated whether infection was related to a reduction in mental wellbeing. Of the participants, 4.9% reported a previous infection. No significant relationship between sex and infection was observed. Prior infection was less frequently reported in subjects aged ≥70 (OR = 0.55; 95% CI: 0.41–0.74) compared to 65–69 years, with no trend after 70 years of age. Those with at least one chronic condition reported a lower infection rate compared to healthy subjects (OR = 0.68; 95% CI: 0.49–0.93). Participants who lived alone more frequently reported infection than those who cohabited (OR = 2.33; 95% CI: 1.29–4.20). Prior infection was related to increased depressive symptoms (OR = 1.57; 95% CI: 1.17–2.10). This representative study of people aged ≥65 years suggests that in Italy, the oldest subjects and chronic patients less frequently exposed themselves to SARS-CoV-2 infection. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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16 pages, 2238 KiB  
Article
The Effect of Waning on Antibody Levels and Memory B Cell Recall following SARS-CoV-2 Infection or Vaccination
by David Forgacs, Vanessa Silva-Moraes, Giuseppe A. Sautto, Hannah B. Hanley, Jasper L. Gattiker, Alexandria M. Jefferson, Ravindra Kolhe and Ted M. Ross
Vaccines 2022, 10(5), 696; https://doi.org/10.3390/vaccines10050696 - 29 Apr 2022
Cited by 10 | Viewed by 2702
Abstract
In order to longitudinally track SARS-CoV-2 antibody levels after vaccination or infection, we assessed anti-RBD antibody levels in over 1000 people and found no significant decrease in antibody levels during the first 14 months after infection in unvaccinated participants, however, a significant waning [...] Read more.
In order to longitudinally track SARS-CoV-2 antibody levels after vaccination or infection, we assessed anti-RBD antibody levels in over 1000 people and found no significant decrease in antibody levels during the first 14 months after infection in unvaccinated participants, however, a significant waning of antibody levels was observed following vaccination. Participants who were pre-immune to SARS-CoV-2 prior to vaccination seroconverted to higher antibody levels, which were maintained at higher levels than in previously infected, unvaccinated participants. Older participants exhibited lower level of antibodies after vaccination, but a higher level after infection than younger people. The rate of antibody waning was not affected by pre-immunity or age. Participants who received a third dose of an mRNA vaccine not only increased their antibody levels ~14-fold, but also had ~3 times more antibodies compared to when they received their primary vaccine series. PBMC-derived memory B cells from 13 participants who lost all circulating antibodies were differentiated into antibody secreting cells (ASCs). There was a significant recall of memory B cell ASCs in the absence of serum antibodies in 5–8 of the 10 vaccinated participants, but not in any of the 3 infected participants, suggesting a strong connection between antibody levels and the effectiveness of memory B cell recall. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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12 pages, 276 KiB  
Article
Willingness to Receive a COVID-19 Vaccine and Associated Factors among Older Adults: A Cross-Sectional Survey in Shanghai, China
by Linlin Wu, Xiaolan Wang, Ruiping Li, Zhuoying Huang, Xiang Guo, Jiechen Liu, Han Yan and Xiaodong Sun
Vaccines 2022, 10(5), 654; https://doi.org/10.3390/vaccines10050654 - 21 Apr 2022
Cited by 11 | Viewed by 1857
Abstract
Background: Older individuals have a high risk of morbidity and mortality due to COVID-19, and one of the most effective ways to prevent COVID-19 is vaccination. Little is known about older people’s willingness to receive a COVID-19 vaccine. Therefore, the objective of this [...] Read more.
Background: Older individuals have a high risk of morbidity and mortality due to COVID-19, and one of the most effective ways to prevent COVID-19 is vaccination. Little is known about older people’s willingness to receive a COVID-19 vaccine. Therefore, the objective of this study was to assess the acceptance of and factors influencing the intention to receive a COVID-19 vaccination among older adults in Shanghai, China. Methods: A cross-sectional study was conducted among older adults (≥60 years old) in Shanghai. Face-to-face interviews with a questionnaire were conducted in community health service centers, recording several parameters: demographic information, health-related factors; perceived likelihood, severity, and burden of COVID-19; perceived safety, effectiveness, necessity, and benefit of the COVID-19 vaccine, as well as their trust in the vaccine delivery system and doctors; willingness to receive a COVID-19 vaccination. Bivariate analysis between several survey items and the willingness to receive a COVID-19 vaccination was conducted using a chi-square test. Logistic regression was used to assess to what degree each variable affected the willingness to receive a COVID-19 vaccination. Results: Of the 1067 participants, 90.91% (970/1067) confirmed that they were willing to receive a COVID-19 vaccination. The participants were more likely to be willing to be vaccinated if they were immigrants (OR = 1.988, 95%CI = 1.062–3.717), had an education level of junior high school (OR = 2.724, 95%CI = 1.000–7.423) or high school or above (OR = 3.993, 95%CI = 1.576–10.119), and had a monthly income of CNY 3000–5000 (OR = 32.770, 95%CI = 1.144–6.711) or CNY >5000 (OR = 2.309, 95%CI = 1.003–5.319). The participants were also more likely to be willing to be vaccinated if they had received a pneumonia vaccination previously (OR = 2.138, 95%CI = 1.016–4.500), perceived the safety of the COVID-19 vaccine (OR = 1.508, 95%CI = 1.073–2.119), perceived the necessity of the COVID-19 vaccine (OR = 2.604, 95%CI = 1.946–3.484), or trusted the suggestions of doctors (OR = 1.706, 95%CI = 1.115–2.618). The participants were less likely to be willing to be vaccinated if they were aged ≥76 years (OR = 0.498, 95%CI = 0.264–0.939), reported a physical health condition of bad or below (OR = 0.229, 95% CI = 0.095–0.549), or were worried about the adverse effects of a COVID-19 vaccination (OR = 0.503, 95%CI = 0.364–0.695). Conclusions: Under the free vaccination policy for COVID-19, older adults have a high intention to be vaccinated to prevent COVID-19 in Shanghai, China. Widely publicizing the safety and necessity of COVID-19 vaccination is necessary. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
12 pages, 1228 KiB  
Article
Detection of Anti-SARS-CoV-2-S1 RBD-Specific Antibodies Prior to and during the Pandemic in 2011–2021 and COVID-19 Observational Study in 2019–2021
by Nadezhda G. Gumanova, Alexander U. Gorshkov, Natalya L. Bogdanova, Andrew I. Korolev and Oxana M. Drapkina
Vaccines 2022, 10(4), 581; https://doi.org/10.3390/vaccines10040581 - 10 Apr 2022
Cited by 4 | Viewed by 1896
Abstract
Background: Longitudinal surveys to monitor the seroprevalence are required to support efforts for assessment of the levels of endemic stability in certain countries. We investigated seroprevalence of anti-SARS-CoV-2-S1 receptor-binding domain (RBD)-specific antibodies in the serum samples in 2011–2021, including a cohort study of [...] Read more.
Background: Longitudinal surveys to monitor the seroprevalence are required to support efforts for assessment of the levels of endemic stability in certain countries. We investigated seroprevalence of anti-SARS-CoV-2-S1 receptor-binding domain (RBD)-specific antibodies in the serum samples in 2011–2021, including a cohort study of 2019–2021, to evaluate the vaccination and anti-IgG-SARS-CoV-2–S1 RBD-positive statuses to assess the resistance and severity of COVID-19. Materials and Methods: Anti-SARS-CoV-2-S1 RBD-specific antibodies were assayed in the serum samples (N = 565) randomly selected from various cohorts previously recruited from 2011 to 2021 from the city of Moscow and Moscow Region. Among them there were the participants (N = 310) recruited in 2019–2021 with an endpoint of 30 October 2021 when these participants were interviewed over phone with relevant questionnaire. Results: Obtained data indicated a percentage of 3–6% of SARS-CoV-2-S1 RBD-specific antibodies detected in participants recruited in 2011–2019. The percentage of SARS-CoV-2-S1 RBD-specific antibodies was increased to 16.5% in 2020 and to 46% in 2021. The vaccination rate of 238 respondents of this cohort was 58% from August 2020 to October 2021. In total, 12% of respondents were hospitalized. The morbidity rate in the subgroup of anti-SARS-CoV-2-S1 RBD-positive respondents was 5.4-fold higher than that in the subgroup of vaccinated respondents. Conclusions: A small percentage of SARS-CoV-2-S1 RBD-specific antibodies detected in 2011–2019 indicated possible spreading of coronaviruses during the pre-pandemic period. Collective immunity in Moscow and the Moscow region was able to reach 69% from August 2020 to October 2021 if this rate is added to the rate of not vaccinated SARS-CoV-2-S1 RBD-positive subjects. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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15 pages, 3506 KiB  
Article
Assessing the Transmissibility of the New SARS-CoV-2 Variants: From Delta to Omicron
by Rui Dong, Taojun Hu, Yunjun Zhang, Yang Li and Xiao-Hua Zhou
Vaccines 2022, 10(4), 496; https://doi.org/10.3390/vaccines10040496 - 24 Mar 2022
Cited by 12 | Viewed by 2716
Abstract
Omicron, the latest SARS-CoV-2 Variant of Concern (VOC), first appeared in Africa in November 2021. At present, the question of whether a new VOC will out-compete the currently predominant variant is important for governments seeking to determine if current surveillance strategies and responses [...] Read more.
Omicron, the latest SARS-CoV-2 Variant of Concern (VOC), first appeared in Africa in November 2021. At present, the question of whether a new VOC will out-compete the currently predominant variant is important for governments seeking to determine if current surveillance strategies and responses are appropriate and reasonable. Based on both virus genomes and daily-confirmed cases, we compare the additive differences in growth rates and reproductive numbers (R0) between VOCs and their predominant variants through a Bayesian framework and phylo-dynamics analysis. Faced with different variants, we evaluate the effects of current policies and vaccinations against VOCs and predominant variants. The model also predicts the date on which a VOC may become dominant based on simulation and real data in the early stage. The results suggest that the overall additive difference in growth rates of B.1.617.2 and predominant variants was 0.44 (95% confidence interval, 95% CI: −0.38, 1.25) in February 2021, and that the VOC had a relatively high R0. The additive difference in the growth rate of BA.1 in the United Kingdom was 6.82 times the difference between Delta and Alpha, and the model successfully predicted the dominating process of Alpha, Delta and Omicron. Current vaccination strategies remain similarly effective against Delta compared to the previous variants. Our model proposes a reliable Bayesian framework to predict the spread trends of VOCs based on early-stage data, and evaluates the effects of public health policies, which may help us better prepare for the upcoming Omicron variant, which is now spreading at an unprecedented speed. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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8 pages, 227 KiB  
Article
COVID-19 in China and the US: Differences in Hospital Admission Co-Variates and Outcomes
by Yulin Cao, Di Wu, Kuo Zeng, Lei Chen, Jianming Yu, Wenjuan He, Li Chen, Wenxiang Ren, Fei Gao, Wenlan Chen, Hongxiang Wang, Robert Peter Gale, Zhichao Chen and Qiubai Li
Vaccines 2022, 10(2), 326; https://doi.org/10.3390/vaccines10020326 - 18 Feb 2022
Viewed by 1635
Abstract
(1) Background: Although there are extensive data on admission co-variates and outcomes of persons with coronavirus infectious disease-2019 (COVID-19) at diverse geographic sites, there are few, if any, subject-level comparisons between sites in regions and countries. We investigated differences in hospital admission co-variates [...] Read more.
(1) Background: Although there are extensive data on admission co-variates and outcomes of persons with coronavirus infectious disease-2019 (COVID-19) at diverse geographic sites, there are few, if any, subject-level comparisons between sites in regions and countries. We investigated differences in hospital admission co-variates and outcomes of hospitalized people with COVID-19 between Wuhan City, China and the New York City region, USA. (2) Methods: We retrospectively analyzed clinical data on 1859 hospitalized subjects with COVID-19 in Wuhan City, China, from 20 January to 4 April 2020. Data on 5700 hospitalized subjects with COVID-19 in the New York City region, USA, from 1 March to 4 April 2020 were extracted from an article by Richardson et al. Hospital admission co-variates (epidemiological, demographic, and laboratory co-variates) and outcomes (rate of intensive care unit [ICU] admission, invasive mechanical ventilation [IMV], major organ failure and death, and length of hospital stay) were compared between the cohorts. (3) Results: Wuhan subjects were younger, more likely female, less likely to have co-morbidities and fever, more likely to have a blood lymphocyte concentration > 1 × 109/L, and less likely to have abnormal liver and cardiac function tests compared with New York subjects. There were outcomes data on all Wuhan subjects and 2634 New York subjects. Wuhan subjects had higher blood nadir median lymphocyte concentrations and longer hospitalizations, and were less likely to receive IMV, ICU hospitalization, and interventions for kidney failure. Amongst subjects not receiving IMV, those in Wuhan were less likely to die compared with New York subjects. In contrast, risk of death was similar in subjects receiving IMV at both sites. (4) Conclusions: We found different hospital admission co-variates and outcomes between hospitalized persons with COVID-19 between Wuhan City and the New York region, which should be useful developing a comprehensive global understanding of the SARS-CoV-2 pandemic and COVID-19. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
14 pages, 2483 KiB  
Article
A Lateral Flow Immunoassay Coupled with a Spectrum-Based Reader for SARS-CoV-2 Neutralizing Antibody Detection
by Rui-Lin Huang, Yi-Chen Fu, Yung-Chih Wang, Chitsung Hong, Wei-Chieh Yang, I-Jen Wang, Jun-Ren Sun, Yunching Chen, Ching-Fen Shen and Chao-Min Cheng
Vaccines 2022, 10(2), 271; https://doi.org/10.3390/vaccines10020271 - 10 Feb 2022
Cited by 9 | Viewed by 3113
Abstract
As of August 2021, there have been over 200 million confirmed case of coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus and more than 4 million COVID-19-related deaths globally. Although real-time polymerase chain reaction is considered to be the primary method [...] Read more.
As of August 2021, there have been over 200 million confirmed case of coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus and more than 4 million COVID-19-related deaths globally. Although real-time polymerase chain reaction is considered to be the primary method of detection for SARS-CoV-2 infection, the use of serological assays for detecting COVID-19 antibodies has been shown to be effective in aiding with diagnosis, particularly in patients who have recovered from the disease and those in later stages of infection. Since it has a high detection rate and few limitations compared to conventional enzyme-linked immunosorbent assay protocols, we used a lateral flow immunoassay as our diagnostic tool of choice. Since lateral flow immunoassay results interpreted by the naked eye may lead to erroneous diagnoses, we developed an innovative, portable device with the capacity to capture a high-resolution reflectance spectrum as a means of promoting diagnostic accuracy. We combined this spectrum-based device with commercial lateral flow immunoassays to detect the neutralizing antibody in serum samples collected from 30 COVID-19-infected patients (26 mild cases and four severe cases). The results of our approach, lateral flow immunoassays coupled with a spectrum-based reader, demonstrated a 0.989 area under the ROC curve, 100% sensitivity, 95.7% positive predictive value, 87.5% specificity, and 100% negative predictive value. As a result, our approach exhibited great value for neutralizing antibody detection. In addition to the above tests, we also tested plasma samples from 16 AstraZeneca-vaccinated (ChAdOx1nCoV-19) patients and compared our approach and enzyme-linked immunosorbent assay results to see whether our approach could be applied to vaccinated patients. The results showed a high correlation between these two approaches, indicating that the lateral flow immunoassay coupled with a spectrum-based reader is a feasible approach for diagnosing the presence of a neutralizing antibody in both COVID-19-infected and vaccinated patients. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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9 pages, 247 KiB  
Article
Seroprevalence of SARS-CoV-2 Antibodies and Associated Factors in Healthcare Workers before the Era of Vaccination at a Tertiary Care Hospital in Turkey
by Meliha Cagla Sonmezer, Enes Erul, Taha Koray Sahin, Ipek Rudvan Al, Yasemin Cosgun, Gulay Korukluoglu, Humeyra Zengin, Gülçin Telli Dizman, Ahmet Cagkan Inkaya and Serhat Unal
Vaccines 2022, 10(2), 258; https://doi.org/10.3390/vaccines10020258 - 08 Feb 2022
Cited by 7 | Viewed by 1981
Abstract
Healthcare workers (HCWs), as frontliners, are assumed to be among the highest risk groups for COVID-19 infection, especially HCWs directly involved in patient care. However, the data on the COVID-19 infection and seroprevalence rates are limited in HCWs. Therefore, we aimed to evaluate [...] Read more.
Healthcare workers (HCWs), as frontliners, are assumed to be among the highest risk groups for COVID-19 infection, especially HCWs directly involved in patient care. However, the data on the COVID-19 infection and seroprevalence rates are limited in HCWs. Therefore, we aimed to evaluate the seroprevalence rates in HCWs according to risk groups for COVID-19 contraction in a large cross-sectional study from a tertiary care hospital in Turkey. We enrolled 1974 HCWs before the vaccination programs. In two separate semi-quantitative ELISAs, either IgA or IgG antibodies against SARS-CoV-2 spike protein subunit 1 (S1) were measured. The proportion of positive test results for IgG, IgA, or both against SARS-CoV-2 of study subjects was 19% (375/1974). Frontline HCWs who had contact with patients (21.7%, RR 2.1 [1.51–2.92]) and HCWs in working in the COVID-19 units, intensive care units, or emergency department (19.7%, RR 1.61 [1.12–2.32]) had a notably higher Anti-SARS-CoV-2 IgG compared to the rest of HCWs who has no daily patient contacts ([11.1%]; p < 0.0001). HCWs who care for regular patients in the medium-risk group have also experienced a sustained higher risk of exposure to SARS-CoV-2. We should enhance the precaution against COVID-19 to protect HCW’s safety through challenging times. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)

Review

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17 pages, 1041 KiB  
Review
Risks and Preventions for Pregnant Women and Their Preterm Infants in a World with COVID-19: A Narrative Review
by Abdulrahman K. Ahmed, Victor Coll Sijercic, Reem Sayad, Gregory R. Ruthig, Sayed F. Abdelwahab, Mohamed A. El-Mokhtar and Ibrahim M. Sayed
Vaccines 2023, 11(3), 640; https://doi.org/10.3390/vaccines11030640 - 13 Mar 2023
Cited by 2 | Viewed by 1999
Abstract
(1) Background and Aim: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is linked to increasing cases of coronavirus disease 2019 (COVID-19) around the world. COVID-19 infections have an important impact on pregnancy, preterm birth (PTB) and delivery. Although several complications have been [...] Read more.
(1) Background and Aim: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is linked to increasing cases of coronavirus disease 2019 (COVID-19) around the world. COVID-19 infections have an important impact on pregnancy, preterm birth (PTB) and delivery. Although several complications have been reported in infected pregnant women, the effect of infection on PTB is controversial. The purpose of this study was to summarize the existing literature on the effects and complications of COVID-19 on the health of pregnant women and preterm babies and its impact on the incidence of PTB. We also discuss the effect of current COVID-19 vaccines during pregnancy. (2) Methods: We carried out a systematic search of MEDLINE, Embase, and PubMed for studies on preterm births associated with COVID-19. (3) Results and Conclusions: We discovered contradictory results regarding the prevalence of PTB during the pandemic compared to earlier years. While most studies indicated an increase in PTBs with COVID-19, some indicated a decline in the preterm delivery rate during this time. During pregnancy, COVID-19 infection can increase the incidence of cesarean section, stillbirth, ICU admission, preeclampsia/eclampsia, and mortality rates. In the treatment of pregnant women with severe COVID-19, methylprednisolone was favored over prednisolone, and a brief course of dexamethasone is advised for pregnant women with anticipated PTB to accelerate the development of the fetal lung. Generally, vaccination for COVID-19 in pregnant and lactating women stimulates anti-SARS-CoV2 immune responses, and it does not result in any noteworthy negative reactions or outcomes for the mother or baby. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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Other

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7 pages, 588 KiB  
Brief Report
Immunization and SARS-CoV-2 Antibody Seroprevalence in a Country with High Vaccination Coverage: Lessons from Chile
by Ximena Aguilera, Claudia González, Mauricio Apablaza, Paola Rubilar, Gloria Icaza, Muriel Ramírez-Santana, Claudia Pérez, Lina Jimena Cortes, Loreto Núñez-Franz, Rubén Quezada-Gaete, Carla Castillo-Laborde, Juan Correa, Macarena Said, Juan Hormazábal, Cecilia Vial and Pablo Vial
Vaccines 2022, 10(7), 1002; https://doi.org/10.3390/vaccines10071002 - 23 Jun 2022
Cited by 5 | Viewed by 1769
Abstract
Chile is among the most successful nations worldwide in terms of its COVID-19 vaccine rollout. By 31 December 2021, 84.1% of the population was fully vaccinated, and 56.1% received booster doses using different COVID-19 vaccines. In this context, we aimed to estimate the [...] Read more.
Chile is among the most successful nations worldwide in terms of its COVID-19 vaccine rollout. By 31 December 2021, 84.1% of the population was fully vaccinated, and 56.1% received booster doses using different COVID-19 vaccines. In this context, we aimed to estimate the prevalence of anti-SARS-CoV-2 antibodies following the infection and vaccination campaign. Using a three-stage stratified sampling, we performed a population-based cross-sectional serosurvey based on a representative sample of three Chilean cities. Selected participants were blood-sampled on-site and answered a short COVID-19 and vaccination history questionnaire using Wantai SARS-CoV-2 Ab ELISA to determine seroprevalence. We recruited 2198 individuals aged 7–93 between 5 October and 25 November 2021; 2132 individuals received COVID-19 vaccinations (97%), 67 (3.1%) received one dose, 2065 (93.9%) received two doses, and 936 received the booster jab (42.6%). Antibody seroprevalence reached 97.3%, ranging from 40.9% among those not vaccinated to 99.8% in those with booster doses (OR = 674.6, 154.8–2938.5). SARS-CoV-2 antibodies were associated with vaccination, previous COVID-19 diagnosis, age group, and city of residence. In contrast, we found no significant differences in the type of vaccine used, education, nationality, or type of health insurance. We found a seroprevalence close to 100%, primarily due to the successful vaccination program, which strongly emphasizes universal access. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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7 pages, 601 KiB  
Brief Report
COVID-19 Infection among Elite Football Players: A Nationwide Prospective Cohort Study
by Dimitrios Papagiannis, Theodoros Laios, Konstantinos Tryposkiadis, Konstantinos Kouriotis, Xenophon Roussis, Georgios Basdekis, Panagiotis Boudouris, Christos Cholevas, Stergios Karakitsios, Pindaros Kakavas, Theoharis Kiriakidis, Panagiotis Kouloumentas, Georgios Kouvidis, Grigoris Manoudis, Pantelis Nikolaou, Christos Theos, Andreas-Nikolaos Piskopakis, Ioannis Rallis, Stavros Ristanis, Alexandros Toliopoulos, Grigoris Zisis, Yiannis Theodorakis, Konstantinos I. Gourgoulianis and Georgios Rachiotisadd Show full author list remove Hide full author list
Vaccines 2022, 10(5), 634; https://doi.org/10.3390/vaccines10050634 - 19 Apr 2022
Cited by 6 | Viewed by 1886
Abstract
Little is known about the risk of COVID-19 infection among footballers. We aimed to investigate the incidence and characteristics of COVID-19 infection among footballers. In total, 480 football players of Super League Greece and 420 staff members participated in a prospective cohort study, [...] Read more.
Little is known about the risk of COVID-19 infection among footballers. We aimed to investigate the incidence and characteristics of COVID-19 infection among footballers. In total, 480 football players of Super League Greece and 420 staff members participated in a prospective cohort study, which took place from May 2020 to May 2021. Nasopharyngeal swabs were collected from footballers and staff members weekly. All samples (n = 43,975) collected were tested using the reverse transcriptase polymerase chain reaction (RT-PCR) test for the detection of “SARS-CoV-2”. In total, 190 positive cases (130 among professional football players and 60 among staff) were recorded. Out of the 190 cases that turned positive, 64 (34%) cases were considered as symptomatic, and 126 (66%) cases were asymptomatic. The incidence rate of a positive test result for footballers was 0.57% (confidence interval (CI) 0.48–0.68%) and for staff members it was 0.27% (CI 0.20%, 0.34%), respectively. Footballers recorded a twofold increased risk of COVID-19 infection in comparison to staff members (relative risk = 2.16; 95% CI = 1.59–2.93; p-value < 0.001). No significant transmission events were observed during the follow-up period. We found a low incidence of COVID-19 infection among professional footballers over a long follow-up period. Furthermore, the implementation of a weekly diagnostic testing (RT-PCR) was critical to break the transmission chain of COVID-19, especially among asymptomatic football players and staff members. Full article
(This article belongs to the Special Issue COVID-19: Epidemiology and Transmission)
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