The protection against Covid-19 offered by the Pfizer and AstraZeneca vaccines shows a decrease in effectiveness five to six months after the second dose is applied. The analysis was published in the ZOE COVID study, carried out in partnership with researchers at King’s College, London, England, and the UK Department of Health and Welfare. The survey of more than 1.2 million people showed that the prevention of coronavirus infection for Pfizer dropped from 88% to 74% and from 77% to 67% for AstraZeneca.
The researchers point out that the results were already expected, mainly due to the rise of the more contagious Delta variant. The research also points out that a drop in protection can occur for a variety of reasons, including preexisting health problems. Anyway, immunizers provide high levels of protection for the majority of the population, which shows the importance of vaccination.
Tim Spector, co-founder of ZOE and leader of the survey, believes that, in the worst-case scenario, protection could fall below 50% for seniors and healthcare professionals by next summer in the European country, in mid-2022.
— The research shows the need for some action. We can’t just sit back and watch protection slowly diminish while cases and the chances of infection are still high,” Spector said in an interview with the BBC.
Last week, another Oxford University study found that the protection of Pfizer and AstraZeneca vaccines against the Delta variant specifically weakens within three months. In the case of Pfizer, the protection rate drops from 75% to 61%. AstraZeneca, on the other hand, decreased from 85% to 68% in 90 days.
ZOE Ltd was founded three years ago to offer personalized nutritional advice based on test kits. The company’s ZOE COVID Symptom Study app, used to collect data from the aforementioned research, is a non-profit initiative in collaboration with King’s College and funded by the Department of Health and Welfare.