Seroprevalence of SARS-CoV-2 and risk factors for infection among children in Uganda: A serial cross-sectional study

PLoS One. 2024 Dec 23;19(12):e0312554. doi: 10.1371/journal.pone.0312554. eCollection 2024.

Abstract

Background: Understanding COVID-19's impact on children is vital for public health policy, yet age-specific data is scarce, especially in Uganda. This study examines SARS-CoV-2 seroprevalence and risk factors among Ugandan children at two timepoints, along with COVID-19-related knowledge and practices in households, including adult vaccination status.

Methods: Baseline surveys were conducted in 12 communities from April to May 2021 (post-Alpha wave) and follow-up surveys in 32 communities from November 2021 to March 2022 (Omicron wave). Household questionnaires and blood samples were collected to test for malaria by microscopy and for SARS-CoV-2 using a Luminex assay. Seroprevalence was estimated at both the survey and community level. Mixed-effects logistic regression models assessed the association between individual and household factors and SARS-CoV-2 seropositivity in children, adjusting for household clustering.

Results: More households reported disruptions in daily life at baseline compared to follow-up, though economic impacts lingered. By the follow-up survey, 52.7% of adults had received at least one COVID-19 vaccine dose. Overall seroprevalence in children was higher at follow-up compared to baseline (71.6% versus 19.2%, p < 0.001). Seroprevalence in children ranged across communities from 6-37% at baseline and 50-90% at follow-up. At baseline, children from the poorest households were more likely to be infected. Increasing age remained the only consistent risk factor for SARS-CoV-2 seroconversion at both timepoints.

Conclusions: Results indicate that a larger number of children were infected during the Delta and Omicron waves of COVID-19 compared to the Alpha wave. This study is the largest seroprevalence survey in children in Uganda, providing evidence that most children were infected with SARS-CoV-2 before the vaccine was widely available to pediatric populations. Pediatric infections were vastly underreported by case counts, highlighting the importance of seroprevalence surveys in assessing disease burden when testing and reporting rates are limited and many cases are mild or asymptomatic.

MeSH terms

  • Adolescent
  • Adult
  • COVID-19* / epidemiology
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Family Characteristics
  • Female
  • Humans
  • Infant
  • Male
  • Risk Factors
  • SARS-CoV-2* / immunology
  • SARS-CoV-2* / isolation & purification
  • Seroepidemiologic Studies
  • Uganda / epidemiology

Grants and funding

We acknowledge sources of funding support including Makerere University Research and Innovations Fund (MAKRIF/DVCFA/026/20) (IB, JFN, JN, MK, PN, IN); Fogarty International Center of the National Institutes of Health (D43TW010526) (IB, JFN, GC, PN, TK, SG, MN, Dr. ST); the Bill and Melinda Gates Foundation, INV-017893 and INV-023690 (JB, IS, BG); and NIH/NIAID (K23 AI166009) to JB. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.