The effectiveness of vaccines against the coronavirus is strongly attenuated six months after the double injection, as highlighted by a British study published Wednesday, August 25, highlighting the importance of boosters.
Based on a panel of nearly one million users of the “ZOE COVID” application, the study shows that the more months pass after a complete vaccination schedule, the more the risk of infection increases. This estimate therefore revives the question, already raised in many countries, of a recall campaign for the fragile public, like the elderly.
“In a reasonable disaster scenario, we could see less than 50% protection for the elderly and health workers by winter,” said Professor Tim Spector, principal researcher in connection with the “ZOE” application COVID ”.
Sign of vaccine waning in new UK report among earliest vaccinees in ZOE COVID study of 1.2 million participants https://t.co/G5mWgp6Qud @bbchealth @timspector
Protection from infection:
Pfizer 88% -> 74% at 4 months
AZ 77% -> 67% at 3 months pic.twitter.com/B6RCPA4QT8
– Eric Topol (@EricTopol) August 25, 2021
In detail, the effectiveness of the Pfizer vaccine goes from 88% one to two months after the injections to 74% five to six months after according to the study analyzed by researchers at King’s College London. The trend is the same for the AstraZeneca vaccine, whose protection is 77% one month after receiving a double injection, against 67% four to five months later.
The study focused on contaminations that occurred between May 26 and July 31, 2021 in people with a complete vaccination schedule and who downloaded the application between December 8, 2020 and July 3, 2021.