Effectiveness of COVID-19 booster vaccines against COVID-19-related symptoms, hospitalization and death in England

Booster vaccination with messenger RNA (mRNA) vaccines has been offered to adults in England starting on 14 September 2021. We used a test-negative case-control design to estimate the relative effectiveness of a booster dose of BNT162b2 (Pfizer-BioNTech) compared to only a two-dose primary course (at least 175 days after the second dose) or unvaccinated individuals from 13 September 2021 to 5 December 2021, when Delta variant was dominant in circulation. Outcomes were symptomatic coronavirus disease 2019 (COVID-19) and hospitalization. The relative effectiveness against symptomatic disease 14-34 days after a BNT162b2 or mRNA-1273 (Moderna) booster after a ChAdOx1-S (AstraZeneca) and BNT162b2 as a primary course ranged from around 85% to 95%. Absolute vaccine effectiveness ranged from 94% to 97% and was similar in all age groups. Limited waning was seen 10 or more weeks after the booster. Against hospitalization or death, absolute effectiveness of a BNT162b2 booster ranged from around 97% to 99% in all age groups irrespective of the primary course, with no evidence of waning up to 10 weeks. This study provides real-world evidence of substantially increased protection from the booster vaccine dose against mild and severe disease irrespective of the primary course. A test-negative case-control analysis of data from the National Immunisation Management System in England demonstrates significant levels of increased protection against hospitalization or death from COVID with mRNA booster vaccines following a primary two-dose course of either ChAdOx1-S or BNT162b2 vaccines.

Automated summary

This study examined the relative and absolute effectiveness of mRNA booster vaccination against COVID-19. The results showed that the booster dose of BNT162b2 or mRNA-1273 had a relative effectiveness ranging from 85% to 95% against symptomatic disease, and an absolute effectiveness ranging from 94% to 97%. For hospitalization or death, the absolute effectiveness of the BNT162b2 booster ranged from 97% to 99% in all age groups. The study provides real-world evidence of significantly increased protection from the booster vaccine dose against mild and severe disease.