Summary: Systematic review of spontaneous reports of myocarditis and pericarditis in transplant recipients and immunocompromised patients following COVID-19 mRNA vaccination

Two years after the start of the COVID-19 pandemic, the scientific response to the SARS-CoV-2 virus is transitioning from the acute to the maintenance phase.  For example, pharmacovigilance has moved from expedited assessments of early signals to working to develop a deeper and broader understanding of the safety of COVID-19 vaccines and medicines. The DSRU is pleased to contribute to the body of pharmacovigilance knowledge on the safety of COVID-19 vaccines with the release of our new systematic review.

We have recently conducted a systematic review of the spontaneously reported events of myocarditis and pericarditis in immunocompromised individuals following mRNA COVID-19 vaccination, from the UK, US, and EU populations. For the purpose of this analysis, we defined immunocompromised people as transplant recipients, HIV/AIDS patients, and cancer patients who were using chemotherapies.

We concluded that these events are rare and not reported more frequently amongst immunocompromised individuals compared to the population overall, however small differences in age and sex distributions were observed. In the overall population, events of myocarditis and pericarditis were predominantly seen in younger males, however amongst immunocompromised people the age distribution was broader, and males and females reported events approximately equally.

The key points of the manuscript are:

1. Myocarditis/pericarditis following COVID-19 mRNA vaccination is rare, and similar reporting rates were observed for immunocompromised and overall populations.
2. Events occurred more frequently in younger males in the population overall; trends in age and sex were less clear for immunocompromised people.
3. Spontaneous reports of myocarditis and pericarditis are not restricted to mRNA vaccines, 385 reports have been submitted to the MHRA following administration of the AstraZeneca COVID-19 vaccine.
4. There was a marginally higher proportion of myocarditis/pericarditis events that met the criteria of “serious” in immunocompromised individuals compared to the overall population.
5. Continued monitoring is important to determine differences in adverse events between population subgroups.
6. Limitations of this study type using spontaneous reporting systems should be noted, these include
   • Underreporting and missing information, which may affect information on comorbidities and concomitant medications.
   • Some immunocompromised people were incorrectly classified as immunocompetent.
   • Further biases may have influenced results, including differences in vaccination strategies between the regions examined, differences in data collected via spontaneous reporting systems, and serious events more likely to be reported to regulators.

The pre-print of this article is available online.

DISCLAIMER

The contents of this article have not been peer-reviewed; it should not replace individual clinical judgement, and the sources cited should be checked. The views expressed in this commentary represent the views of the authors. These views are not a substitute for professional medical advice.