Pfizer-BioNTech assures that a third dose of its anti-Covid vaccine provides even more effective immune protection against SarS-CoV-2. The two companies will seek authorization to do so from the FDA. They also announced the development of a version of their Covid-19 vaccine specifically targeting the Delta variant.
Pfizer and BioNTech announced Thursday that they were developing a version of the coronavirus vaccine targeting the Delta variant, which today accounts for nearly 50% of contaminations in France. This new vaccine will target the entire spike protein of the virus and not just part of it as is the case with the currently proposed vaccine. Clinical trials are expected to begin in August.
Both companies also report "promising results" from studies of people who received a third dose of their original vaccine. According to them, a booster administered six months after the second dose of the vaccine would increase the strength of the antibodies by five to ten times against all variants.
Note that this data has not been peer reviewed. They have therefore not been officially published in a scientific journal. Still, Pfizer and BioNTech plan to submit their findings to the Food and Drug Administration (FDA) in the coming weeks.
In a joint press release with the Centers for Disease Control and Prevention, the American health authority nevertheless issued a reservation following this announcement, emphasizing that fully vaccinated Americans do not need a booster at this time. "We are prepared to receive booster doses if and when science demonstrates that they are necessary “, said the two agencies.
For their part, citing data from Israel, Pfizer and BioNTech suggested that the effectiveness of their vaccine "to prevent both infection and disease symptomatic had decreased within six months after vaccination. Additionally, health officials in Israel estimated that the full vaccination coverage offered by the Pfizer-BioNTech vaccine was only 64% effective against the Delta variant.
Nevertheless, Israel's estimates have been contradicted by other studies concluding that the vaccine is highly effective in preventing infection against all variants. “Pfizer seems opportunistic in snagging an ad based on very early, undigested data from Israel “, asserts John Moore, virologist at Weill Cornell Medicine in New York.
Finally, some experts have also questioned talk of recalls for Americans when much of the world has yet to receive even a a single dose. “It is impossible to ignore the world situation “said Natalie Dean, a biostatistician at Emory University in Atlanta. "It's hard for me to imagine getting a third dose when there are frontline workers treating Covid patients who still haven't been vaccinated “.
