There have been a handful of reports of patients developing pericarditis, an inflammation of the sac that surrounds the heart after receiving two doses of an mRNA vaccine.

Canada’s chief public health officer Dr. Theresa Tam says the numbers aren’t beyond what is normally seen outside of a mass vaccination campaign and it affects mostly young males.

“In general they are relatively mild illnesses and some have been hospitalized for a short stay and they are being monitored for a longer period to see how they recover but their symptoms appear to improve quickly, “explained Dr. Tam.

Health officials are closely monitoring the small number of cases in Canada, as most young males haven’t yet received two vaccine doses. Dr. Tam says the symptoms to look for include chest pain, shortness of breath or an irregular heartbeat.

Officials in Israel and the U.S are also monitoring reports of pericarditis in patients.