booster dose for these vaccines. What we don’t know is: How urgent is the need?”
An estimated 103 million Americans are now fully vaccinated with Pfizer’s formula, 69 million with Moderna’s and 15 million with J&J’s, according to the CDC. Regulators took up the question of Pfizer boosters first because the company submitted its data ahead of the other vaccine makers.
In the new review of Moderna’s latest data, the FDA did not indicate if it was leaning toward approving the company’s booster shot. The agency did say that vaccines used in the United States still provide protection, and it raised questions about some of Moderna’s efficacy data, the AP reports.
The two initial Moderna shots contain 100 micrograms of vaccine each. But the drugmaker said in documents filed with the FDA that 50 micrograms ought to be enough for a booster for healthy people.
A company study of 344 people gave them a 50-microgram shot six months after their second dose, and levels of virus-fighting antibodies jumped. Moderna said the booster even triggered a 42-fold rise in antibodies able to target the highly contagious Delta variant.
Side effects were similar to the fevers and aches that Moderna recipients commonly experience after their second regular shot, the company says.
How efficient is the J&J booster shot?
As for people who got the J&J vaccine, the company has submitted data to the FDA for two different options: a booster shot at two months or at six months. The company said in its FDA submission that a six-month booster is recommended but that a second dose could be given at two months in some situations, according to the AP.
J&J released data in September showing that a booster given at two months provided 94% protection against moderate-to-severe COVID-19 infection. The company has not disclosed patient data on a six-month booster, but early measures of virus-fighting antibodies suggest it provides even higher protection.
Even without a booster, J&J says, its vaccine remains about 80% effective at preventing COVID-19 hospitalizations.
Scientists emphasize that all three vaccines still offer strong protection against severe disease and death from COVID-19. The thorny issue is how quickly, and how much, protection against milder infection may wane.