, according to a new study published on the bioRxiv preprint server.
In the study, which hasn’t yet been peer-reviewed or formally published in a medical journal, researchers analyzed blood samples from 46 healthy young or middle-aged adults after receiving two doses, and then 6 months after the second dose.
“Our study shows vaccination with the Pfizer-BioNTech vaccine induces high levels of neutralizing antibodies against the original vaccine strain, but these levels drop by nearly 10-fold by 7 months,” the researchers told Reuters.
In about half of the adults, neutralizing antibodies were undetectable at 6 months after the second dose, particularly against coronavirus variants such as Delta, Beta, and Mu.
Neutralizing antibodies only make up part of the body’s immune defense against the virus, Reuters noted, but they are still “critically important” in protecting against coronavirus infections.
“These findings suggest that administering a booster dose at around 6 to 7 months following the initial immunization will likely enhance protection,” the study authors wrote.
BioNTech said a new vaccine formula will likely be needed by mid-2022 to protect against future mutations of the virus, according to the Financial Times.
“This year, [a different vaccine] is completely unneeded, but by mid-next year, it could be a different situation,” Ugur Sahin, MD, cofounder and CEO of BioNTech, told the news outlet.
Current variants, namely the Delta variant, are more contagious than the original coronavirus strain but not different enough to evade current vaccines, he said. But new strains may be able to evade boosters.
“This virus will stay, and the virus will further adapt,” Dr. Sahin said. “This is a continuous evolution, and that evolution has just started.”
A version of this article first appeared on WebMD.com.