ABSTRACT
Intro: Children and Young people were the last group in England be offered COVID-19 vaccination (from September 2021), thus were the largest susceptible group when SARS-CoV-2 Omicron variants emerged. We monitored vaccine and naturally-derived antibodies in schools between November 2021 and March 2022. Method(s): We conducted three large surveys (November 2021, January and March 2022) in a nationally representative random sample of primary and secondary schools, stratified by regions. Oral fluid samples were tested for IgG antibodies against SARS-CoV-2 nucleocapsid (anti-NP) and spike (anti-S1) proteins using novel validated ELISAs;vaccines used in England elicit anti-S1 antibodies only. We calculated weighted prevalences for each survey, and used multilevel logistic regression to investigate associations with socio-demographic factors. Finding(s): Overall 11311 students contributed 22478 biological samples (respectively 4840, 7549 and 10089 in rounds 1, 2 and 3, with similar socio- demographic characteristics). In 4-11 year olds, not eligible for vaccination, anti- S1 and anti-NP antibody prevalences were 31.3% and 26.6%, 46.2% and 43.8%, and 53.4% and 58.7% respectively over the three rounds. The corresponding estimates in 12 to 18 year olds) were 70.7% and 34.6%, 85.6% and 45.9%, 89.0 and 53.9%. In November 2021 (before Omicron dominance), higher anti-S1 antibody positivity was associated with older age and Black ethnicity, and non- eligibility for free school meals in 4-11 year olds. In 12-18 years it was associated with non-eligibility for free school meals. In March 2022 when Omicron dominated, these associations remained, together with urban location in 4-11 years old. Conclusion(s): The steep increase in 4-11 year olds in both sets of antibodies reflected the emergence and spread of highly infectious Omicron variants whilst high and increasing anti-S1 prevalence in secondary students was consistent with greater vaccine uptake. Socioeconomically deprived 12-18 year olds had lower odds of anti-S1, suggesting lower vaccine uptake or access.Copyright © 2023
ABSTRACT
INTRODUCTION: Despite reports suggesting an association between COVID-19 mRNA vaccination and pericarditis and myocarditis, detailed nationwide population-based data are sparsely available. We describe the incidence of pericarditis and myocarditis by age categories and sex after COVID-19 mRNA vaccination from a nationwide mass vaccination programme in Singapore. METHODS: The incidence of adjudicated cases of pericarditis and myocarditis following COVID-19 mRNA vaccination that were reported to the vaccine safety committee between January to July 2021 was compared with the background incidence of myocarditis in Singapore. RESULTS: As of end July 2021, a total of 34 cases were reported (9 pericarditis only, 14 myocarditis only, and 11 concomitant pericarditis and myocarditis) with 7,183,889 doses of COVID-19 mRNA vaccine administered. Of the 9 cases of pericarditis only, all were male except one. The highest incidence of pericarditis was in males aged 12-19 years with an incidence of 1.11 cases per 100,000 doses. Of the 25 cases of myocarditis, 80% (20 cases) were male and the median age was 23 years (range 12-55 years) with 16 cases after the second dose. A higher-than-expected number of cases were seen in males aged 12-19 and 20-29 years, with incidence rates of 3.72 and 0.98 case per 100,000 doses, respectively. CONCLUSION: Data from the national registry in Singapore indicate an increased incidence of pericarditis and myocarditis in younger men after COVID-19 mRNA vaccination.