Association of SARS-CoV-2 Seropositivity and Symptomatic Reinfection in Children in Nicaragua

IMPORTANCE: The impact of the SARS-CoV-2 pandemic on children remains unclear. Better understanding of the burden of COVID-19 among children and their risk of reinfection is crucial, as they will be among the last groups vaccinated. OBJECTIVE: To characterize the burden of COVID-19 and assess how risk of symptomatic reinfection may vary by age among children. DESIGN, SETTING, AND PARTICIPANTS: In this prospective, community-based pediatric cohort study conducted from March 1, 2020, to October 15, 2021, 1964 nonimmunocompromised children aged 0 to 14 years were enrolled by random selection from the Nicaraguan Pediatric Influenza Cohort, a community-based cohort in District 2 of Managua, Nicaragua. Additional newborn infants aged 4 weeks or younger were randomly selected and enrolled monthly via home visits. EXPOSURES: Prior COVID-19 infection as confirmed by positive anti–SARS-CoV-2 antibodies (receptor binding domain and spike protein) or real-time reverse transcriptase–polymerase chain reaction (RT-PCR)–confirmed COVID-19 infection at least 60 days before current COVID-19 infection. MAIN OUTCOMES AND MEASURES: Symptomatic COVID-19 cases confirmed by real-time RT-PCR and hospitalization within 28 days of symptom onset of a confirmed COVID-19 case. RESULTS: This cohort study assessed 1964 children (mean [SD] age, 6.9 [4.4] years; 985 [50.2%] male). Of 1824 children who were tested, 908 (49.8%; 95% CI, 47.5%-52.1%) were seropositive during the study. There were also 207 PCR-confirmed COVID-19 cases, 12 (5.8%) of which were severe enough to require hospitalization. Incidence of COVID-19 was highest among children younger than 2 years (16.1 cases per 100 person-years; 95% CI, 12.5-20.5 cases per 100 person-years), which was approximately 3 times the incidence rate in any other child age group assessed. In addition, 41 symptomatic SARS-CoV-2 episodes (19.8%; 95% CI, 14.4%-25.2%) were reinfections. CONCLUSIONS AND RELEVANCE: In this prospective, community-based pediatric cohort study, rates of symptomatic and severe COVID-19 were highest among the youngest participants, with rates stabilizing at approximately 5 years of age. In addition, symptomatic reinfections represented a large proportion of symptomatic COVID-19 cases.