Effectiveness of COVID-19 vaccination against school absenteeism in children and adolescents hospitalized with COVID-19

Background: COVID-19 vaccination has been recommended for children to protect them and to enable in-person educational and social activities. Methods: We estimated COVID-19 vaccination effectiveness (VE) against school absenteeism in children 5-17 years old hospitalized from September 1, 2021 through May 31, 2023. Full vaccination was defined as two vaccine doses. Results: We studied 231 children admitted to hospital with COVID-19, including 206 (89.2 %) unvaccinated/ partially vaccinated and 25 (10.8 %) fully vaccinated. Unvaccinated/partially vaccinated children were absent from school for longer periods compared to fully vaccinated children (median absence: 14 versus 10 days; pvalue = 0.05). Multivariable regression showed that full COVID-19 vaccination was associated with fewer days of absence compared to no/partial vaccination on average (adjusted relative risk: 0.77; 95 % CI: 0.61 to 0.98). COVID-19 VE was 50.7 % (95 % CI: -11.3 % to 78.2 %) for school absenteeism above the median duration of absenteeism. Conclusions: Full COVID-19 vaccination conferred protection against school absenteeism in hospitalized schoolaged children with COVID-19.