Members of the U.S. military who were vaccinated against Covid-19 showed higher-than-expected rates of heart inflammation, although the condition was still extremely rare, according to a study released on June 29.

Israel’s Health Ministry found the small number of heart inflammation cases observed mainly in young men who received Pfizer’s Covid-19 vaccine in Israel were likely linked to the company’s vaccination.

The U.S. Centers for Disease Control and Prevention (CDC) has not found a link between heart inflammation and Covid-19 vaccines, the agency’s Director Rochelle Walensky said on April 27.

Checkpoint inhibitors have become popular treatments for cancers, but a New England Journal of Medicine article may give physicians pause before prescribing them.