The Janssen COVID-19 vaccine is now limited to certain individuals ages 18 and up after the U.S. Food and Drug Administration downgraded its emergency use authorization.

AstraZeneca’s Covid-19 vaccine carries a small extra risk of rare blood clots with low platelets after the first dose and no extra risk after the second, a study led and funded by the drugmaker showed on July 28, after worries over side effects.