Reviewing myocarditis and pericarditis in immunosuppressed individuals following COVID-19 mRNA vaccination

By Tarun Sai LomteDec 30 2021Reviewed by Aimee Molineux

A team of researchers recently compared the reporting rates of myocarditis and pericarditis between immunocompromised patients and the overall population to investigate a possible link between coronavirus disease-2019 (COVID-19) mRNA vaccines and these conditions, and posted their findings to the medRxiv* preprint server.

COVID-19 remains a major health concern across the world ever since it was first reported in Wuhan, China, in late 2019. The prime response to effectively regulate and mitigate pandemic-related health crises was the development of various vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, several vaccines like Pfizer and Moderna mRNA vaccines and viral vector-borne vaccines like Oxford’s ChAdOX1 and Sputnik V. have been approved by the World Health Organization (WHO) for emergency use.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

COVID-19 mRNA vaccines are the first-ever nucleic acid-based vaccines to be approved for use. Unlike conventional vaccines, mRNA vaccines can be modified for use against new variants when needed, for example, during the present global surge of COVID-19 cases dominated by the rapid transmission of the SARS-CoV-2 Omicron variant. However, more research is required to ascertain the potential adverse effects of mRNA vaccines, given the widespread implementation of booster doses across several countries.

The study

Following the administration of SARS-CoV-2 mRNA vaccines, a surge in myocarditis, pericarditis, and myopericarditis was noted in Europe and the United States (US). About 26-57 cases per million were reported within the first week of commencement of vaccination in Europe, which was up to 40.6 per million in the US following the administration of the second dose. Inflammation of the myocardium and pericardium causes myocarditis and pericarditis leading to chest pain, shortness of breath, cardiac failure, palpitations, and abnormal heart rhythms.

In the present study, researchers investigated the possible correlation between the mRNA vaccines and the said medical conditions through a systematic review. The researchers utilized EudraVigilance (EU/EEA) and Vaccine Adverse Event Reporting System (US) data for the analysis.

Results

There were 49 immunocompromised patients among 5681 patients reporting either myocarditis or pericarditis or both in the European Union(EU)/ European Economic Area (EEA). Two cases reported both myocarditis and pericarditis, while 30 and 21 cases were of pericarditis and myocarditis, respectively; 38 cases were noted as serious (defined as prolonged hospitalization or life-threatening or fatal outcome).

Cancer drugs were the most common concomitant medication. Over 57% of the reported cases involved males, whereas 61.2% of the cases involved patients in the 18-64 years age group. While 156 of the 5681 cases reported fatal outcomes, no fatality was recorded in the immunocompromised patients.

In the US, more than 3000 cases of myocarditis or pericarditis were recorded following mRNA vaccine administration, of which 57 cases (1.86%) were of immunocompromised patients. More than 52% of these events were observed in males and more than half of them were below 60 years of age. These events were predominantly observed after the administration of the second dose of the mRNA vaccine and around 70% of these cases were observed within 14 days of vaccination. Over 68% of the cases were found to be serious and one fatality was noted in the US eight days after first vaccination in a patient receiving cancer therapy. Although the cause of death was not specified, autopsy reported systemic inflammatory reaction. The team observed a slight increase (about 5%) in serious cases in the immunocompromised category compared to the overall population.

Limitations

The study relied on data that is publicly available which might lack exhaustive information due to underreporting and/or faulty classification of immunocompromized as immunocompetent. Further, the researchers did not report incidence rates on the exposed population due to the lack of data, and neither did they include an unexposed comparison group for analysis.

Conclusions

From the observations made in this study, it could be noted that there was little evidence to conclusively mark differences in frequency of myocarditis and pericarditis cases between immunosuppressed individuals and the overall population. Further, the cases were more pronounced in the US as they were reported following the second dose within 14 days, while no particular trends were observed based on demographics or sex.

The study noted that mRNA vaccines elicit a T-cell mediated immune response, particularly the CD4+ T cells, and myocarditis or pericarditis post-vaccination could be due to the activity of CD4+ T cells. It is also known that immunocompromised individuals have diminished B and T lymphocyte activity, which could also increase the risks of adverse effects following mRNA vaccination.

In conclusion, the present study did not conclusively correlate the incidence of myocarditis or pericarditis with mRNA vaccination, as these events are rarely observed after vaccination. More research is required to characterize the prognosis of these events following mRNA vaccine administration.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources