Boosters cut COVID-19 risks—here’s what the latest evidence shows and why it matters.
A large English study involving more than 3 million adults who received autumn 2022 booster shots finds that booster vaccination lowers the chances of COVID-19–related hospitalisation and death. Led by researchers from the universities of Bristol and Oxford, the work adds to the growing body of proof that booster doses enhance protection against severe outcomes from COVID-19.
Published in Vaccine on 18 February, the findings indicate that the effectiveness of the Moderna (BA.1 mRNA-1273) and Pfizer-BioNTech (BA.1 BNT162b2) boosters was similar, though the level of protection diminished with time.
We already know that the initial COVID-19 vaccines reduce the risk of severe illness. This new study, conducted at the NIHR Bristol Biomedical Research Centre, examined the impact of a booster dose for people who had already completed prior vaccination.
The research focused on adults aged 50 and over who received either Moderna or Pfizer-BioNTech boosters during England’s autumn 2022 booster campaign. Using linked GP and hospital records within the OpenSAFELY platform, the NHS England–approved study compared 3,464,877 individuals eligible for a booster with a similarly matched group who did not receive one.
Participants were matched on age, time since last vaccine dose, brand of prior vaccination, clinical vulnerability, and geographic region. They were then followed for about a year to track COVID-19–related hospitalisations and deaths.
Among roughly 2.5 million people monitored for a year, the study recorded 14,436 COVID-19 hospitalisations, 1,152 COVID-19 deaths, 32,184 non-COVID-19 deaths, and 52,758 fractures.
Key findings show that within 350 days, boosted individuals had substantially lower risks of COVID-19 hospitalisation (3.78 per 1,000 people) compared with those unboosted (6.81 per 1,000), and lower risks of death from COVID-19 (0.29 per 1,000 vs 0.61 per 1,000). In other words, boosters roughly halved the risk of severe COVID-19 outcomes. Protection was strongest in the first roughly 70 days and waned over time.
Moderna and Pfizer–BioNTech boosters produced comparable outcomes for COVID-19–related results, though there was a slight uptick in non–COVID-19 mortality in the Moderna group.
The researchers also explored whether booster vaccination influenced fracture risk—a finding not plausibly causal. They observed a small reduction in fracture risk among boosted individuals, which likely reflects residual confounding (other factors that relate to both getting a booster and fracture risk). The overall tiny fracture effect supports the validity of the main conclusions.
Lead author Dr. Paul Madley-Dowd, a Research Fellow in Medical Statistics and Health Data Science at the University of Bristol, commented: “Our findings reinforce the importance of booster vaccination against COVID-19 among people over 50. The study adds further evidence that boosters reduce the risk of hospitalisation and death.”
Funding for this work came from NHS England, the Wellcome Trust, UK Research and Innovation’s MRC, NIHR, NIHR Bristol BRC, OpenSAFELY, and the Bennett Institute for Applied Data Science.
For full details, see the paper: ‘Effectiveness of bivalent BA.1 mRNA booster vaccines during the autumn 2022 COVID-19 booster programme in adults aged 50+ in England: observational matched cohort study using OpenSAFELY’ by Paul Madley-Dowd et al., in Vaccine.
Public release: This material reflects the authors’ and organization’s current views and is provided for clarity and context. For the original source, see Mirage News here: https://www.miragenews.com/booster-jabs-reduce-risks-of-covid-deaths-study-1622755/.
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