Peer-reviewed article
COVID-19 vaccine effectiveness in the paediatric population aged 5-17 years: a multicentre cohort study using electronic health registries in six European countries, 2021 to 2022.
Soares P, Machado A, Nicolay N, Monge S, Sacco C et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study examined how well COVID-19 vaccines protected children and adolescents aged 5-17 years against severe illness requiring hospitalisation across six European countries from 2021 to 2022. The researchers tracked over 8 million children using health records to compare vaccinated and unvaccinated children. Vaccines provided strong protection in the first three months after vaccination, but protection declined over time and varied depending on which virus variant was circulating.
Key points
- Overall vaccine effectiveness against COVID-19 hospitalisation in 12-17-year-olds without prior infection was 69%
- Vaccine effectiveness was highest in the first 3 months (77%) and declined to 48% by 6-12 months after vaccination
- Protection varied by variant: 94% against Delta, 56% against Omicron BA.1/BA.2, and 41% against BA.4/BA.5
- In children with previous SARS-CoV-2 infection, one dose provided 80% effectiveness
- Protection estimates were similar for 5-11-year-olds but were less precise due to smaller numbers
Limitations
The study measures hospitalisation outcomes only and does not assess protection against milder infection. It cannot determine whether differences in vaccine effectiveness reflect true biological differences or differences in testing and hospitalisation practices across countries.
Abstract
BackgroundDuring the first year of the COVID-19 pandemic, vaccination programmes targeted children and adolescents to prevent severe outcomes of SARS-CoV-2 infection.AimTo estimate COVID-19 vaccine effectiveness (VE) against hospitalisation due to COVID-19 in the paediatric population, among those with and without previously documented SARS-CoV-2 infection.MethodsWe established a fixed cohort followed for 12 months in Denmark, Norway, Italy, Luxembourg, Navarre (Spain) and Portugal using routine electronic health registries. The study commenced with paediatric COVID-19 vaccination campaign at each site between June 2021 and January 2022. The outcome was hospitalisation with a laboratory-confirmed SARS-CoV-2 infection or COVID-19 as the main diagnosis. Using Cox proportional hazard models, VE was estimated as 1 minus the confounder-adjusted hazard ratio of COVID-19 hospitalisation between vaccinated and unvaccinated. A random-effects meta-analysis was used to pool VE estimates.ResultsWe included 4,144,667 5-11-year-olds and 3,861,841 12-17-year-olds. In 12-17-year-olds without previous infection, overall VE was 69% (95% CI: 40 to 84). VE declined with time since vaccination from 77% ≤ 3 months to 48% 180-365 days after immunisation. VE was 94% (95% CI: 90 to 96), 56% (95% CI: 3 to 80) and 41% (95% CI: -14 to 69) in the Delta, Omicron BA.1/BA.2 and BA.4/BA.5 periods, respectively. In 12-17-year-olds with previous infection, one dose VE was 80% (95% CI: 18 to 95). VE estimates were similar for 5-11-year-olds but with lower precision.ConclusionVaccines recommended for 5-17-year-olds provided protection against COVID-19 hospitalisation, regardless of a previously documented infection of SARS-CoV-2, with high levels of protection in the first 3 months of the vaccination.
Findings the Hub has extracted
Each claim below is labelled by its type of design and links back to this report.
- Intervention
- COVID-19 vaccination
- Population
- 4,144,667 children aged 5-11 years and 3,861,841 adolescents aged 12-17 years across Denmark, Norway, Italy, Luxembourg, Spain, and Portugal
Key finding