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Study Illuminates the Diminishing Efficacy of COVID-19 Vaccines Over Time

A study by the UK Health Security Agency analyzing over 10 million COVID-19 cases revealed that vaccination significantly lowers the risk of death, with the most pronounced effect seen within six months of vaccination. The findings, which underscore the success of the vaccination program and the need for booster doses, are published in the Journal of the Royal Society of Medicine. Credit: SciTechDaily.com

Research from the UK Health Security Agency shows that COVID-19First identified in 2019 in Wuhan, China, COVID-19, or Coronavirus disease 2019, (which was originally called "2019 novel coronavirus" or 2019-nCoV) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has spread globally, resulting in the 2019–22 coronavirus pandemic.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>COVID-19 vaccinations greatly reduce death risk, especially within six months of receiving a dose, highlighting the importance of booster shots.

The risk of death from COVID-19 decreases significantly after vaccination but this protection diminishes after six months, providing evidence for continued booster doses, a new study has found.

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).

Vaccination and Decreased Fatality

The Case Fatality Risk (CFR) — the proportion of cases that resulted in death — was cross-referenced with vaccination status, revealing a clear association between vaccination and reduced mortality. Notably, the study highlights a crucial timeframe — within six months of the last vaccine dose — when CFR was consistently at its lowest across all age groups. After this, the protective benefit began to wane and CFR increased.

Notable Findings in Older Adults

The research underscores the success of the COVID-19 vaccination program in reducing mortality rates.

Among adults over 50, CFR was 10 times higher in the unvaccinated (6.3%) compared to those who had been vaccinated within six months prior to testing positive (0.6%). The study also reveals a steep decline in CFR in early 2021, aligning with the initial vaccine rollout.

Florence Halford from the UKHSA’s COVID-19 Vaccines and Epidemiology Division said: “COVID-19 Case Fatality Risk reduced after vaccination, with the lowest seen across all age bands when vaccinated up to six months prior to the specimen date. This provides some evidence for continued booster doses in older age groups.”

Reference: “Temporal changes to adult case fatality risk of COVID-19 after vaccination in England between May 2020 and February 2022: a national surveillance study” by Florence Halford, Kathryn Yates, Tom Clare, Jamie Lopez-Bernal, Meaghan Kall and Hester Allen, 13 December 2023, Journal of the Royal Society of Medicine.
DOI: 10.1177/01410768231216332

Source: SciTechDaily