Following a review of suspected adverse reaction reports of myocarditis and pericarditis following Covid-19 vaccination, MHRA is advising that health professionals should be alert to the signs and symptoms of these conditions.

Vaccinated individuals should seek immediate medical attention should they experience new onset of chest pain, shortness of breath, palpitations or arrhythmias.

As of 16 June the MHRA had received 87 Yellow Card reports of myocarditis and pericarditis as suspected side effects from the Pfizer/BioNTech vaccine and four reports after the Moderna vaccine.

Up to that date an estimated 16.8 million first doses and 10.9 million second doses of the Pfizer/BioNTech vaccine had been administered, and approximately 730,000 first doses of the Moderna vaccine.

The side effects have occurred most frequently in younger males aged 40 years and younger, and within 10 days after the second dose. Most of the cases were mild and individuals typically recovered within a short time with symptomatic treatment and rest.

The product information for both the PfizerBioNTech and Moderna vaccines has been updated to reflect the new advice.

While reports of myocarditis and pericarditis after vaccination with the AstraZeneca Covid-19 vaccine have also been received, there is insufficient evidence to recommend similar warnings for this vaccine.