ATAGI says extra caution is warranted with the Pfizer vaccine for patients with inflammatory cardiac illness, current acute rheumatic fever, complex or severe congenital heart disease or acute decompensated heart failure, plus patients aged 12-29 with dilated cardiomyopathy and any cardiac transplant recipients.

Patients with a history of congenital heart disease, cardiac transplant or cardiomyopathy could now receive the Pfizer or Moderna vaccine “without any precautions”, it said.

However, those with inflammatory cardiac illness currently or in the past six months, acute rheumatic fever, acute rheumatic heart disease or acute decompensated heart failure were still advised to consult a GP or other specialist prior to vaccination.

ATAGI is urging these patients to consult a GP, cardiologist or immunisation specialist before vaccination to weigh the benefits and potential risks.

All patients administered the Pfizer vaccine should be warned of the symptoms of myocarditis/pericarditis, including chest pain, palpitations, syncope and shortness of breath or pain when breathing, ATAGI says.

While the typical time to onset is 1-5 days after inoculation.

It’s important to assess for the presence of other causes of myocarditis or pericarditis and for other more common causes of the patient’s symptoms, including acute coronary syndrome, the experts add.

“If patients who are investigated for myocarditis and/or pericarditis have a normal ECG and troponin, they should be advised to avoid high-intensity exercise or competitive sports until symptoms have subsided and to return for assessment in 1-2 days if symptoms are ongoing.

“If clinical suspicion of myocarditis or pericarditis is high, a cardiologist should be consulted even if investigation results are normal.”

One gap in the advice is whether patients with a confirmed case linked to the first dose of the vaccine should get a second dose of the same vaccine.

Meanwhile, a new US study suggests myocarditis and pericarditis linked to the vaccine are “distinct syndromes” that affect different cohorts.

Published in the Journal of the American Medical Association, the data from 40 US hospitals identified 20 cases of myocarditis and 37 cases of pericarditis after COVID-19 vaccination from two million patients mostly administered Pfizer’s or Moderna’s mRNA vaccine.

The average age of myocarditis patients was 36, and the average time to symptom onset was 3.5 days.

In contrast, pericarditis occurred 15 times after a first dose and 22 times after a second dose.

The average age of pericarditis patients was 59.

For both conditions, about 75% of affected patients were male