The South Korean government said on Friday that it is closely watching overseas cases of reported heart inflammation in young recipients of the Pfizer and Moderna COVID-19 vaccines. 

Kwon Jun-wook, deputy head of the Korea Disease Control and Prevention Agency(KDCA), made the remark in a media briefing of Friday, noting that there are not many young people in South Korea who have received the vaccines in question and that it would steadily monitor the cases overseas. 

He said authorities are also reviewing measures to improve monitoring and early response systems regarding the matter. 

The U.S. Centers for Disease Control and Prevention(CDC) said on Thursday, citing data from two vaccine safety monitoring systems, that a higher-than-expected number of young men have experienced heart inflammation after their second shot of the mRNA-based COVID vaccines, Pfizer and Moderna. 

The U.S. agency, however, said that a full assessment is underway and that it has yet to conclude on a causal relationship between the vaccines and the cases of myocarditis or pericarditis.