mRNA-1273 vaccine effectiveness against symptomatic SARS-CoV-2 infection and COVID-19-related hospitalization in children aged 6 months to 5 years

Abstract

IMPORTANCE: Data on mRNA-1273 (Moderna) vaccine effectiveness in children aged 6 months to 5 years are limited. OBJECTIVE: To assess mRNA-1273 vaccine effectiveness against symptomatic SARS-CoV-2 infection and COVID-19-related hospitalization among children aged 6 months to 5 years. DESIGN, SETTING, AND PARTICIPANTS: A test-negative study using linked health administrative data in Ontario, Canada. Participants included symptomatic children aged 6 months to 5 years who were tested by RT-PCR. EXPOSURES: mRNA-1273 vaccination. MAIN OUTCOMES AND MEASURES: Symptomatic SARS-CoV-2 infection and COVID-19-related hospitalization. RESULTS: We included 3467 test-negative controls and 572 test-positive cases. Receipt of mRNA-1273 was associated with reduced symptomatic SARS-CoV-2 infection (VE=90%; 95%CI: 53, 99%) and COVID-19-related hospitalization (VE=82%; 95%CI: 4, 99%) ≥7 days after the second dose. CONCLUSIONS and RELEVANCE: Our findings suggest mRNA-1273 vaccine effectiveness is initially strong against symptomatic SARS-CoV-2 infection and hospitalization in children aged 6 months to 5 years. Further research is needed to understand long-term effectiveness and the need for booster doses