Heart Inflammation After COVID-19 Vaccine is Rare

The overall risk of myopericarditis following COVID-19 vaccination is very low, affecting 18 people per million vaccine doses, shows a new study published in The Lancet Respiratory Medicine.

Researchers examined international databases, looking at more than 400 million vaccination doses, to compare the risk of myopericarditis following vaccination against COVID-19 and other diseases such as influenza and smallpox.

‘Among COVID-19 vaccinations, the risk of myopericarditis was higher for those who received mRNA vaccines (22.6 cases per million doses) compared to non-mRNA vaccines (7.9 cases per million doses).’

They found no statistically significant difference between the incidence of myopericarditis following the COVID-19 vaccination (18 cases per million doses) and other vaccinations (56 cases per million doses).

"Our research suggests that the overall risk of myopericarditis appears to be no different for this newly approved group of vaccines against COVID- 19, compared to vaccines against other diseases. The risk of such rare events should be balanced against the risk of myopericarditis from infection and these findings should bolster public confidence in the safety of COVID-19 vaccinations," says Dr. Kollengode Ramanathan, a cardiac intensivist at National University Hospital, Singapore, and corresponding author.

Myopericarditis is a condition that causes inflammation of the heart muscle and, in some cases, severe permanent heart damage. It is most often caused by viruses but can also occur after vaccination in rare instances.

There have been reports of myopericarditis following mRNA-based COVID-19 vaccination, especially in adolescents and young adults. A new study aimed to determine whether this increase in reporting was due to a true increase in incidence or a result of improved reporting systems and recall bias.

Researchers analyzed more than 20 studies from international databases with reported incidences of myopericarditis following any type of vaccination between January 1947 and December 2021.

Of these, 11 studies looked specifically at COVID-19 vaccinations, covering over 395 million COVID-19 vaccine doses - nearly 300 million of which were mRNA vaccines. The rest of the studies covered other vaccinations such as smallpox (2.9 million doses), influenza (1.5 million doses), and others [2] (5.5 million doses).

The rate of myopericarditis following COVID-19 vaccination was 18 cases per million doses. For all other viral vaccinations combined, the rate of myopericarditis was 56 cases per million doses.

Reported cases were also higher in people below the age of 30 (40.9 cases per million doses), males (23 cases per million doses), and following the second dose of COVID-19 vaccine (31.1 cases per million doses).

To put the findings into context with the risk of myopericarditis following COVID-19 infection, researchers conducted a post-study analysis.

Among 2.5 million patients who were hospitalized with COVID-19, many of whom had clinical or radiological suspicion of myopericarditis, 1.1% had myopericarditis.

However, while these figures provide a frame of reference, the results are not directly comparable with the number of cases of myopericarditis following COVID-19 vaccination due to different units of measurement.

In addition, comparisons have been made across different periods for different vaccines. Diagnostic tools might have differed or not been available leading to lower reporting of cases in earlier studies.



Source: Medindia