Last reviewed 13 July 2021

The Medicines and Healthcare Products Regulatory Agency (MHRA) has updated safety warnings for Pfizer and Moderna vaccines after “extremely rare” reports of myocarditis and pericarditis.

The MHRA and the Government’s independent expert advisory body, the Commission on Human Medicines (CHM), conducted a thorough review of suspected adverse reaction reports of myocarditis and pericarditis following Covid-19 vaccination and have revised the information on vaccines for healthcare professionals and the public.

People who have been vaccinated are being told to seek immediate medical attention if they experience chest pain, shortness of breath or arrhythmia.

The MHRA received 60 Yellow Card reports of myocarditis and 42 of pericarditis after the Pfizer vaccination up to 23 June, as well as 1 viral pericarditis and 1 streptococcal endocarditis.

For Moderna, there have been 5 reports of myocarditis and 2 of pericarditis, the regulator said.

Cases occurred most frequently in young men and after the second dose, although they were usually mild, and the patients recovered in a short time.

In the latest issue of the MHRA’s Drug Safety Update, it said: “The Covid-19 vaccines remain highly effective in protecting people from Covid-19 and have already saved thousands of lives.

“These events are extremely rare and tend to be mild when they do occur. Our advice remains that the benefits of getting vaccinated outweigh the risks in the majority of people.

“It is still vitally important that people come forward for their first and second vaccination when invited to do so, unless advised otherwise.”