If the new recommendations sound confusing, outside experts say it makes sense to consider extra protection for the most vulnerable. That’s because a CDC study that tracked which boosters J&J recipients initially chose concluded a Moderna or Pfizer second shot was superior to a second J&J dose. For the more than 4 million who got Moderna or Pfizer as their second shot, the CDC says an additional booster is only necessary if they meet the newest criteria - a severely weakened immune system or are 50 or older. Of the 1.3 million who got a second J&J shot, the CDC said now they may choose a third dose - either Moderna or Pfizer. What about people who got Johnson & Johnson’s single-dose shot? They already were eligible for one booster of any kind. Only the Pfizer vaccine can be used in those as young as 12 Moderna’s is for adults. Tuesday’s decision allows them another booster, too - a fifth dose.

Vaccines have a harder time revving up severely weak immune systems, and Marks said their protection also tends to wane sooner. Until now, the FDA had allowed a fourth vaccine dose only for the immune-compromised as young as 12. Pfizer had asked the FDA to clear a fourth shot for people 65 and older, while Moderna requested another dose for all adults “to provide flexibility” for the government to decide who really needs one.įDA’s Marks said regulators set the age at 50 because that’s when chronic conditions that increase the risks from COVID-19 become more common.

Moderna 2nd booster shot timing