After getting vaccinated, the risk of dying from COVID-19 significantly decreases, but this protection wanes after six months, providing evidence for the need for booster doses, according to a new study.
Researchers from the UK Health Security Agency (UKHSA) analyzed more than 10 million cases of COVID-19 in adults between May 2020 and February 2022. Their findings are published in the Journal of the Royal Society of Medicine (JRSM).
The Case Fatality Risk (CFR) – the proportion of cases leading to death – was compared with vaccination status, revealing a clear link between vaccination and reduced mortality. The study particularly highlights a crucial timeframe – within six months of the last vaccine dose – during which the CFR was consistently lowest across all age groups. After this period, the protective benefits began to diminish, and the CFR increased.
The research underscores the success of the COVID-19 vaccination program in lowering mortality rates.
Among adults over 50, the CFR in unvaccinated individuals was ten times higher (6.3%) compared to those who were vaccinated within six months before the positive test (0.6%). The study also shows a significant decline in CFR in early 2021, aligning with the initial rollout of the vaccine.
The risk of death from COVID-19 cases decreased after vaccination, with the lowest value observed across all age groups when the vaccination occurred up to six months before the sample date. This provides some evidence for continued booster doses in older age groups.“
– Florence Halford, Department of COVID-19 Vaccines and Epidemiology, UKHSA
Halford, F., et al. (2023). Temporal changes in the mortality risk of COVID-19 in adults after vaccination in England between May 2020 and February 2022: a national surveillance study. Journal of the Royal Society of Medicine. doi.org/10.1177/01410768231216332.