Good news – myocarditis from COVID vaccines is mild and self-resolving in teenagers

Children who develop myocarditis because of an mRNA vaccine typically experience “mild and self-resolving” symptoms, according to Victorian doctors.

Myocarditis – or inflammation of the heart– is a known but rare side-effect of the mRNA vaccines.

A report published in the Medical Journal of Australia is the largest for a single children’s hospital, with data studied from 33 adolescents who presented to Monash Children’s Hospital with diagnosed or probable myocarditis.

Data suggest it is more likely experienced as a complication of COVID-19, rather than from the vaccination against the disease.

Based on the Therapeutic Goods Administration’s most recent COVID-19 vaccine safety report, it occurs in around 2 in 100,000 those to receive the Moderna or Pfizer vaccinations, although it is slightly more common in boys aged 12-17 and men 18-29.

In general, symptoms experienced by patient at Monash Children’s Hospital were mild and required no major treatment.

All case recovered with the administration of ibuprofen and an average hospital stay of 2.3 days.

It’s an encouraging finding that should give parents of children peace-of-mind, says one of the report’s authors Dr Suraj Varma, a paediatric cardiologist at Monash Children’s Hospital.

“The traditional forms of myocarditis can be very serious,” Varma tells Cosmos.

The kids who presented with myocarditis after vaccination have had a very mild disease, as far as clinical findings are concerned.

“And since writing the paper, we’ve had follow-up at three-to-six months for some of them, and all of them are doing very well, without any problems, and they are back to their usual sports and school and activities which is incredibly reassuring.

Varma says traditional forms of myocarditis can be very serious, including with admission to ICU. It is also more likely to occur, and with greater severity, in unvaccinated people.

“And even though there is a small risk of side effects associated with the vaccine, the risk with not getting the vaccine is at least 10 times higher,” Varma says.

“So if you got COVID-19, your risk of having significant problems was much, much higher than any potential side effects that could be occurring after taking the vaccine.”

The patients whose data was analysed as part of this study will be followed up one year after their discharge from hospital.

“With the way things are going, it’s remained a mild disease so far, which is very reassuring.”

Over 95% of the population has received two doses of approved vaccines, and no more than 2 in 100,000 to receive an mRNA-based vaccine experience myocarditis, so the risk of the side-effect remains very low.