The first study directly comparing COVID-19 boosters found that most shots improved immune responses in fully vaccinated people, but there is no obvious “winner” to help make a decision. .

(The trial was conducted back in June; since then, CureVac scrapped development of its first-generation COVID-19 vaccine candidate. Valneva and Novavax are still seeking authorization for their vaccines in the U.K. The other shots have received authorization there.)?

clinical trial were all fully vaccinated with either AstraZeneca’s vaccine or Comirnaty, BioNTech and Pfizer’s shot. The study only included people older than 30 years old who have never tested positive for the virus.

(The people who were initially immunized with AstraZeneca’s shot did not generate a different immune response with the same shot as a booster.).

(In both the U.S. and the U.K., Moderna’s booster is authorized as a half dose.) Novavax’s shot was the best tolerated, in terms of side effects

And, finally, as stated, AstraZeneca’s shot doesn’t do very much as a booster among people already immunized with the same vaccine

That means, for example, that people who got the single-shot J&J vaccine can choose between a second J&J jab or a booster dose of Comirnaty or Moderna’s vaccine. 

That research found that antibody levels were highest from a Moderna booster, then Pfizer, and then J&J; however, the study wasn’t designed to compare the vaccine combinations

has stopped short of telling people what is the best booster based on their primary vaccination series and is instead encouraging people to sign up for whatever shot they choose

continue to urge people who were vaccinated before June to get a booster shot

People who got J&J’s COVID-19 shot can get a booster

Here’s why COVID-19 booster shots are good for business

Allowing people to mix COVID-19 vaccines could cut into Pfizer and Moderna’s revenue next year