Europe’s drug regulator on June 11 identified another rare blood condition as a potential side effect of AstraZeneca’s Covid-19 vaccine and said it was looking into cases of heart inflammation after inoculation with all coronavirus shots.

Preliminary findings from two vaccine safety monitoring systems suggest a higher-than-expected number of cases of heart inflammation after the second dose of mRNA Covid-19 vaccines in young men, the U.S. Centers for Disease Control and Prevention (CDC) said on June 10.

Some teenagers and young adults who received Covid-19 vaccines experienced heart inflammation, a U.S. Centers for Disease Control and Prevention advisory group said, recommending further study of the rare condition.