Millions of Americans already received the shot, which will go by brand name Spikevax, under emergency authorization.

The decision from the Food and Drug Administration (FDA) on Monday makes Moderna’s the second COVID-19 vaccine to receive full approval right behind Pfizer’s, which was approved last August.

The FDA hopes the approval will encourage more people to get vaccinated. As of Jan. 30 more than, 211 million, or 63 percent, of Americans were fully vaccinated according to the Centers for Disease Control and Prevention.

What about side effects? The FDA considered data collected from people who received doses since Dec. 2020. It said serious side effects were relatively rare.

However, the vaccine includes a warning about myocarditis and pericarditis, rare types of heart inflammation seen predominantly in young men after the second dose. The agency is withholding approval of the vaccine for children ages 12 to 17 until further testing is done.

This story originally appeared in WORLD. © 2022, reprinted with permission. All rights reserved.