SARS-CoV-2 seroprevalence among learners in grades 1-7, their parents and teachers in KwaZulu-Natal, South Africa : a cross-sectional study

Abstract

INTRODUCTION : There is limited information on SARS-CoV-2 seroprevalence among children and adolescents in LMIC school settings. We aimed to assess (1) the seroprevalence of SARS-CoV-2 antibodies, (2) prevalence of self-reported or confirmed SARS-CoV-2 prior infections and, (3) COVID-19 symptoms (including long-COVID) among a cohort of primary school learners, their parents and teachers in a semi-rural school setting approximately 3-years into the COVID-19 pandemic. METHODS : Learners in grades 1-7 attending two pre-selected schools in close proximity in the Ndwedwe area, iLembe district, KwaZulu-Natal, South Africa, their parents and teachers were invited to enroll into the COVID Kids Schools Study (CoKiDSS) - a cross-sectional survey conducted between May-August 2023. All participants provided informed consent, completed a questionnaire and provided a fingerprick of blood for SARS-CoV-2 antibody testing using the COVID-19 IgG/IgM Rapid Test. Statistical methods included descriptive analysis, jackknife-estimated seroprevalence and incidence (unadjusted and sensitivity-adjusted), and logistic regression using generalized linear models. RESULTS : A total of 645 participants (i.e., 456 learners, 147 parents and 42 teachers) were enrolled into the survey. Overall SARS-CoV-2 IgG seroprevalence was 78% unadjusted to 81% adjusted with an increasing seropositivity trend, from learners to teachers (76% unadjusted to 79% adjusted in learners, 79% unadjusted to 82% adjusted in parents and 93% unadjusted to 97% adjusted in teachers). About 2.6% of learners tested IgM seropositive. Interestingly, 17% of the participants, including 20% learners, tested negative for SARS-CoV-2 antibodies. While only 16 participants (2.5% - 2 learners, 10 parents, and four teachers) self-reported a prior confirmed SARS-CoV-2 infection. Of these 2 learners (100%), eight parents (80%) and 4 teachers (100%) reported COVID-19 like symptoms that persisted for ≥28-days. CONCLUSION : We reported high SARS-CoV-2 IgG seroprevalence among learners in grades 1-7, their parents and teacher approximately 3 years into the COVID-19 pandemic which may be attributed to the snowball effect of multiple waves of infection in South Africa. However, only a small proportion of participants self-reported prior COVID-19 infection. This may be due to (1) recall bias and participants' perception of low susceptibility to and severity of COVID-19, (2) limited access to SARS-CoV-2 testing, and/or (3) a high prevalence of asymptomatic infections.