A new study which reinforces fears of a vaccine protection limited in time in the face of Covid-19.

The protection against the coronavirus conferred by the vaccines of Pfizer / BioNtech and Oxford / AstraZeneca decreases significantly after six months, indicates a British study on Wednesday, arguing according to its authors in favor of recall campaigns.

74% infection protection six months after injection for Pfizer

One month after receiving the second dose, the Pfizer vaccine prevents 88% of being contaminated with Covid-19, but this protection drops to 74% after five to six months, according to the latest study analysis Zoe Covid.

For AstraZeneca's vaccine, efficacy drops from 77% one month after administration of the second dose to 67% after four to five months, says study, based on data collected from around one million users of the Zoe app, set up by a private group of the same name, and analyzed by researchers at King's College London and Zoe's team.

The latter analyzed the contaminations that occurred between May 26 and July 31, 2021 in people who loaded the application between December 8, 2020 and July 3, 2021 after being vaccinated.

The British vaccination campaign, which has currently given a second dose to 77% of those over 16, has targeted the elderly and those considered fragile as well as healthcare workers.

These groups are therefore, according to King's College researchers, those in which protection has diminished the most.

"Urgent to plan for vaccine boosters"

"In a reasonable disaster scenario, we could see less than 50% protection for the elderly and health workers by winter," said Professor Tim Spector, scientist at the head of the project.

If this figure concerns contaminations and not severe forms, this could translate into "an increase in hospitalizations and deaths" if the country is subjected to high levels of contamination and a highly transmissible variant.

This is why the researcher considers it "urgent to plan for vaccine boosts", which would also imply thinking about the relevance of the vaccination of minors, "according to vaccine resources".

This question of the recall is now being considered by several countries, including the United Kingdom which intends to offer a new dose to the most vulnerable from September despite the reluctance of the World Health Organization (WHO) which would like to prioritize the vaccination of countries poor.

Health

Anti-Covid vaccination: Five questions around the third dose

Health

Coronavirus: No need for third dose now from a scientific point of view, according to WHO 

  • Covid 19

  • Coronavirus

  • Health

  • Vaccination

  • Anti-covid vaccine