Who is eligible?

The FDA approved only a half-dose booster of Moderna for seniors over 65 as well as 18- to 64-year-old adults who are at high-risk for COVID-19 (whether because of health conditions, their jobs, or their living situation) who received their initial shot of Moderna at least six months ago. These are the same groups that the CDC approved for the Pfizer-BioNTech booster.

How soon can I get a booster shot?

The boosters are now available now at thousands of vaccination sites, including local pharmacies. Over 100 million fully vaccinated people are now eligible for boosters, according to the New York Times.

What if I got a different vaccine?

Whether you received Pfizer, Johnson & Johnson, or Moderna vaccines, if you’re eligible for a booster, you’re allowed to receive a different brand than your original COVID vaccine. Boosters are recommended for Pfizer recipients who had their final vaccine dose more than six months ago and are either over 65 or are at high-risk for COVID-19 because of health conditions, their jobs, or their living situation. Boosters are recommended for all Johnson & Johnson recipients who had their shot more than 2 months ago. A study conducted by the National Institutes of Health—which has not yet been peer reviewed—indicated that mixing and matching was safe and effective. No matter which vaccine you received initially, the Moderna booster will only be a half-dose. Here’s how to decide which booster is right for you.

Do Moderna recipients really need a booster?

Scientists are divided on the necessity of Moderna booster shots. Many have emphasized that the vaccine’s first two doses already leave recipients well-protected from severe illness. A study published in August found that Moderna was 93% effective against hospitalization, compared to 88% for Pfizer, and 71% for J&J. While Pfizer’s efficacy dropped to 77% after four months, Moderna’s remained high.

I received the Moderna shot, but I’m not in a high-risk group. When will I be able to get a booster?

It’s hard to say. The FDA said there’s “not a lot of appetite for moving down the age range very significantly, if at all” when it comes to expanding booster shot eligibility. For now, the focus seems to remain on high-risk and vulnerable groups, with undetermined plans to include younger Americans.

Update, October 22, 2021: This article has been updated with information about the rollout of the Moderna booster.