(Reuters) — Advisers to the U.S. Centers for Disease Control and Prevention are set to meet on Wednesday to assess the possibility of a link between rare cases of heart inflammation and the mRNA COVID-19 vaccines from Pfizer and partner BioNTech and from Moderna.

The CDC has been investigating cases of heart inflammation mainly in young men for several months. The Israeli health ministry earlier this month said it saw a possible link between such cases and Pfizer’s COVID-19 vaccine.

During the committee meeting, set to begin at 11 a.m. ET, the agency will present details of more than 300 confirmed cases of myocarditis and pericarditis reported to CDC and the Food and Drug Administration among the over 20 million adolescents and young adults vaccinated in the United States, CDC Director Rochelle Walensky said during a White House briefing last week.

The CDC earlier this month said it was still evaluating the risk from the condition and did not confirm a causal relationship between the vaccines and the heart issue.

The agency, however, said a higher-than-expected number of young men have experienced heart inflammation after their second dose of the mRNA COVID-19 shots, with more than half the cases reported in people between the ages of 12 and 24.

The Advisory Committee on Immunization Practices (ACIP) will discuss the benefits of the mRNA vaccines versus the potential risk to adolescents and young adults from the heart condition, according to the agency’s agenda.

Although health officials in Israel have determined that there is likely a link between vaccination and the heart inflammation, concerns about the more infectious Delta coronavirus variant have prompted the country to urge 12-to 15-year olds get vaccinated.

Pfizer, whose vaccine has been authorized for use in Americans as young as 12, previously said it had not observed a higher rate of heart inflammation than would normally be expected in the general population.

Moderna had said it could not identify a causal association with the heart inflammation cases and its vaccine.

Over 138 million Americans have so far been fully vaccinated with one of the two mRNA vaccines, according to CDC data as of Monday.