Heart inflammation cases in young men higher than expected after mRNA vaccines: US CDC

WASHINGTON (REUTERS) – 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 US Centres for Disease Control and Prevention (CDC) said on Thursday (June 10).

More than half of the myocarditis or pericarditis cases reported to the US Vaccine Adverse Event Reporting System after patients had received either the Pfizer/BioNTech or Moderna vaccines were in people between the ages of 12 and 24, the CDC said.

Those age groups accounted for less than nine per cent of the doses administered.

“We clearly have an imbalance there,” Dr Tom Shimabukuro, deputy director of the CDC’s Immunisation Safety Office, said in a presentation to an advisory committee to the US Food and Drug Administration that is meeting on Thursday.

He said that the Vaccine Safety Datalink (VSD) – another safety monitoring system – showed an increased incidence of the heart inflammation in 16 to 39 year olds after their second dose of the shots when compared to the rate observed after their first dose.

The limited data shows that most of the patients – at least 81 per cent of them – had a full recovery from their symptoms, Shimabukuro said.

Pfizer and Moderna were not immediately available for comment.

Israel’s Health Ministry has said it found a likely link to vaccination in a small number of myocarditis cases observed mainly in young men who received Pfizer’s Covid-19 vaccine.

The CDC said it will hold a meeting of its Advisory Committee on Immunisation Practices next week to further evaluate the evidence and assess the risk of myocarditis following mRNA vaccination for Covid-19.

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