Initial protection against SARS-CoV-2 omicron lineage infection in children and adolescents by BNT162b2 in Israel: an observational study

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Research in context

Evidence before this study

We searched PubMed, Google Scholar, medRxiv and relevant journals for studies of COVID-19 vaccine effectiveness in children and adolescents, using search terms such as “COVID-19 vaccine effectiveness” and search terms that included the younger age groups, including “COVID-19 vaccine effectiveness children”, and “COVID-19 vaccine effectiveness adolescents”, without any language restrictions. The search was done on June 20, 2022. For each relevant paper, we further looked at its references and papers that cited it. Because vaccinations for children were only approved on Oct 29, 2021, we only searched for studies from Dec 1, 2021, or later. We found three highly relevant papers—one analysing New York (USA) data, and two reports by the US Centers for Disease Control and Prevention (CDC). These reports showed that a two-dose BNT162b2 vaccine regimen in children aged 5–11 years reduced confirmed infection rates of the omicron variant (B.1.1.529) by around 2 times in the first weeks after vaccination, and that a booster dose in adolescents aged 12–15 years reduced confirmed infection rates by around 3 times compared with a second dose.

Added value of this study

Our findings add to the existing evidence on the vaccine effectiveness of BNT162b2 against confirmed SARS-CoV-2 infection in young age groups, which is scarce. Our results show that the BNT162b2 vaccine provided an initial increased protection of around 2 times against infection in children aged 5–10 years. The estimated protection is in line with the vaccine effectiveness results estimated in the USA for a similar study period and time from receipt of the vaccine. Vaccine effectiveness in our study was somewhat higher than that reported by the CDC, possibly because of waning immunity, because more time had passed since vaccination in the CDC study. Our analysis further showed that a recent booster dose in adolescents decreased infections by around 3–4 times compared with in the internal control, which is similar to estimates from the reported by the CDC.

Implications of all the available evidence

The findings of the current study join existing evidence of the BNT162b2 vaccine in children and adolescents against confirmed SARS-CoV-2 infection while omicron was dominant and can support policy making decisions regarding vaccination regimes for young age groups. Future studies are needed to assess the duration of this protection and protection against other outcomes such as paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 and long-COVID.

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