The FDA will limit the vaccine’s availability later this year to older adults and those who may be at risk of severe illness.

After a six-week delay, the US Food and Drug Administration has approved Novavax’s Covid-19 vaccine, according to a letter from the agency, but only for people 65 and older and those 12 and up who have at least one underlying condition that puts them at higher risk of severe illness.

Healthy and under the age of 65? You might not need to receive an annual COVID-19 booster. What to know about new guidelines.