In a U.S. surveillance study from July 2022–September 2023, vaccinated children aged 6 months–4 years had fewer ED visits and hospitalizations with COVID-19 than unvaccinated children.

SARS-CoV-2 infects children of all ages and can cause severe disease and even death. In 2022, mRNA vaccines (initially approved for adults, then for older children) were approved for children as young as 6 months. Still, recent CDC data. opens in new tab showed that 63% of children aged 6 months–17 years and 90% of those aged 6 months–4 years remained unvaccinated. Perception of vaccine effectiveness may be a contributing factor to vaccine acceptance.

The New Vaccine Surveillance Network (NVSN) enrolled children aged 6 months through 4 years who were seen for acute respiratory illness at seven U.S. pediatric centers from July 2022 through September 2023. In a test-negative case-control study, researchers compared children with and without COVID-19 and verified vaccination status who were seen in the emergency department (ED), were hospitalized, or both. Among 7434 enrollees (5.0% with a positive SARS-CoV-2 test), 86.0% were completely unvaccinated against COVID-19, 3.8% had received one dose of vaccine, and 10.4% had received ≥2 doses. Higher vaccination rates were noted in older and white children. Vaccine effectiveness for preventing ED visits or hospitalization in those receiving >2 vaccine doses was 40.0% when compared to unvaccinated children.

Comment

Despite factors that complicate a clear interpretation of these data (e.g., rising rates of natural infection, greater likelihood of vaccine coverage in children with underlying conditions), the most striking information is the overall low rate of vaccine coverage in the youngest age group approved for vaccination. The particularly low rate in non-white children also deserves attention during focused efforts to address vaccine inaccessibility or hesitancy.