Objective: Subsequent protection from severe acute respiratory syndrome-related coronavirus 2 (SARS-COV-2) infection in pediatrics is not well reported in the literature. We aimed to describe the clinical characteristics and dynamics of SARS-CoV-2 PCR repositivity in children. 

Design: This is a population-level retrospective cohort study

Setting: Patients were identified through multiple national-level electronic coronavirus disease 2019 (COVID-19) databases covering all Kuwait's primary, secondary and tertiary centers.

Participants: The study included children 12 years and younger over an 11-month period between 2020 and 2021. SARS-CoV-2 reinfection was defined as having two or more positive SARS-CoV-2 PCR done on a respiratory sample, at least 45 days apart. Clinical data were obtained from the Pediatric COVID-19 Registry in Kuwait (PCR-Q8).

Primary and secondary outcome measures: The primary measure is to estimate the SARS-CoV-2 PCR repositivity rate. The secondary objective was to establish average duration between first and subsequent SARS-CoV-2 infection. Descriptive statistics was used to present clinical data for each infection episode. Also, incidence-sensitivity analysis was performed to evaluate 60- and 90-day PCR repositivity intervals.

Results: Thirty pediatric COVID-19 patients had SARS-CoV-2 reinfection at an incidence of 1.02 (95% CI 0.71-1.45) infection per 100,000 person-days and a median time to reinfection of 83 days (IQR 62-128.75). The incidence of reinfection decreased to 0.78 (95% CI 0.52-1.17) and 0.47 (95% CI 0.28-0.79) per person-days when the minimum interval between PCR repositivity was increased to 60 and 90 days, respectively. The mean age of reinfected subjects was 8.5 years (IQR 3.7-10.3) and the majority (70%) were females. Most children (55.2%) had asymptomatic reinfection. Fever was the most common presentation in symptomatic patients. One immunocompromised experienced two reinfection episodes.

Conclusion: SARS-CoV-2 reinfection is uncommon in children. Previous confirmed COVID-19 in children seems to result in milder reinfection.

This is a population-level retrospective cohort study that included children 12 years and younger over an 11-month period between 2020 and 2021. Patients were identified through multiple national-level electronic coronavirus disease 2019 (COVID-19) databases. SARS-CoV-2 reinfection was defined as having two or more positive SARS-CoV-2 PCR done on a respiratory sample, at least 45 days apart. Clinical data were obtained from the Pediatric COVID-19 Registry in Kuwait (PCR-Q8). Descriptive statistics and incidence-sensitivity analyses were performed.

The study was approved by the ethical board of the Ministry of Health, Kuwait (reference no. 1607/2020).