Seroprevalence and factors associated with SARS-CoV-2 Seropositivity among children in 32 Districts in Uganda

Abstract

Although the epidemiology and clinical presentation of SARS-CoV-2 is well described in adult population, the SARS-CoV-2 infection epidemiology in the pediatric population, especially in the sub-Saharan Africa is not well known. Uganda’s testing protocols set up to diagnose cases with SARS-CoV-2 infections as well as monitor the disease burden in the country mainly target symptomatic patients, travelers and contacts of index SARS-CoV-2 infected patients. Ugandan children rarely travel out of the country and as in other regions, when infected with SARS-CoV-2 infections are often asymptomatic. This means that many of the children infected with SARS-CoV-2 in the country are missed out leading to under-reporting of the disease burden in this age-group.Objective: To determine the seroprevalence and factors associated with SARS-CoV-2 seropositivity among children in 32 districts in Uganda.Methodology: This was a cross-sectional study nested in a cluster-randomized trial that sought to evaluate the impact of long-lasting insecticidal nets (LLINs) treated with pyrethroid plus pyriproxyfen vs LLINs treated with pyrethroid plus piperonyl butoxide (PBO) on malaria incidence in 32 districts in Uganda. Serological testing for antibody (IgG) response to SARS-CoV-2 spike protein was performed on dry blood spot samples collected for all children in the enrolled households using a Luminex assay. Data extraction from the primary study questionnaire was done to collect information on demographics, clinical features, geographical distribution, household, contact and travel characteristics for analysis of factors associated with SARS-CoV-2 seropositivity. Data was exported to STATA (Version 17) for analysis. Descriptive statistics, cross tabulations, bivariate and multi variable analysis was conducted with p values <0.05 considered significant. Results: A total of 2,803 participants were studied, 1457 (51.9%), were female. Most of the enrolled participants 1735 (61.8%) were aged 3 to 12 years. The SARS-CoV-2 seroprevalence was found to be 52.2% (1,464 out of 2,803 participants) with the highest seroprevalence in Acholi (60.7%) region. The factors found to be associated with SARS-CoV-2 seropositivity included older age (aPR=1.09, p=0.011 for children aged 3 to 12 years, compared to those less than 3 years), report of fever in the past two weeks (aPR=0.86, p=0.049), presence of sore throat at the time of the survey (aPR=0.62, p=0.035) and reported history of travel out of the village of residence in the past one month (aPR=1.19, p=0.014).9Conclusion: The seroprevalence of SARS-CoV-2 among children in Uganda before the country adopted nationwide vaccination for children was 52.2%. Older age, report of fever in the past two weeks, presence of a sore throat at the time of survey and reported travel out of the village were found to be significantly associated with SARS-CoV-2 seropositivity. These findings provide a baseline for monitoring trends in seropositivity with increasing vaccine uptake and emergence of new variants in children. Ongoing surveillance will be important to monitor the effects of vaccination and future SARS-CoV-2 variants in children. Key words; Children, Seroprevalence, SARS-CoV-2