FDA intends to put its most serious warning on Covid vaccines, sources say

One study estimated that in their first year of use, Covid-19 vaccinations averted almost 20 million deaths around the world. Patrick T. Fallon/AFP/Getty Images/File

The US Food and Drug Administration intends to put a “black box” warning on Covid-19 vaccines, according to two people familiar with the agency’s plans.

A boxed warning, which appears at the top of prescribing information for medicines, is the agency’s most serious, designed to warn about risks such as death or life-threatening or disabling reactions that should be weighed against the intervention’s benefits. They can also be used when a risk might be lowered by using a medicine in a targeted way, such as only in certain groups.

Boxed warnings on opioids, for example, warn about risks of abuse, addiction, overdose and d