Coronavirus vaccine protection fades within six months, UK study finds

The ZOE Covid-19 study was based on data from more than a million app users, underscoring the need for booster shots

It found the Pfizer/BioNTech efficacy fell from 88 to 74 per cent, and Oxford/AstraZeneca dropped from 77 to 67 per cent after four to five months

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A patient receives a dose of the Pfizer-BioNTech coronavirus vaccine in the US. Photo: AFP

Published: 10:03pm, 25 Aug 2021Updated: 10:03pm, 25 Aug 2021

Protection against Covid-19 offered by two doses of the Pfizer/BioNTech and the Oxford/AstraZeneca vaccines begins to fade within six months, underscoring the need for booster shots, according to researchers in Britain.

After five to six months, the effectiveness of the Pfizer jab at preventing Covid-19 infection in the month after the second dose fell from 88 to 74 per cent, an analysis of data collected in Britain’s ZOE Covid-19 study showed.

For the AstraZeneca vaccine, effectiveness fell from 77 to 67 per cent after four to five months.

The study was based on data from more than a million app users, comparing self-reported infections in vaccinated participants with cases in an unvaccinated control group.

More data is needed in younger people because participants who had their shots up to six months ago tended to be elderly as that age group was prioritised when the shots were first approved, the study authors said.

ZOE Ltd was founded three years ago to offer customised nutritional advice based on test kits. The company’s ZOE Covid-19 Symptom Study app is a not-for-profit initiative in collaboration with King’s College London and funded by the Department of Health and Social Care.