Burden of SARS‐CoV‐2 infection prior to vaccine eligibility among immunocompromised children aged 1–11 years at a pediatric tertiary referral hospital in Toronto, Canada

SARS-CoV-2 seroprevalence reflects the efficacy of pandemic infection prevention and control measures. We performed anti-spike IgG serological testing on residual sera of children 1-11 years old at a tertiary care referral center between October and November 2021. Immunocompromised patients had the highest SARS-CoV-2 seroprevalence, at 40.5%, compared to 19.3% in non-immunocompromised patients. Targeted infection prevention and public health interventions are warranted for pediatric immunocompromised patients in future pandemics.