Systematic review of spontaneous reports of myocarditis and pericarditis in transplant recipients and immunocompromised patients following COVID-19 mRNA vaccination
Authors: Lane Samantha , Yeomans Alison , Shakir Saad 
Published: December 2021

AbstractObjectivesTo determine whether spontaneous reporting rates of myocarditis and pericarditis differed in immunocompromised patients compared to the whole population overall, and in terms of demographics, vaccine dose, and time-to-onset.DesignSystematic review of spontaneously reported data from the European Union/European Economic Area (EU/EEA), the United States (US) and the United Kingdom (UK).Data SourcesEudraVigilance (EU/EEA), Vaccine Adverse Event Reporting System (VAERS; US) and the Medicines and Healthcare products Regulatory Agency (MRHA, UK) spontaneous reporting databases were searched from date of vaccine launch to 01 December 2021.Eligibility criteriaPublicly available spontaneous reporting data for “Myocarditis” and “Pericarditis” from EU/EEA and US following COVID-19 mRNA vaccines. Reports with comorbidities or concurrent medication indicative of transplantation, HIV infection, or cancer (“immunocompromised” population) were compared with each overall database population.Data extraction and synthesisTwo researchers extracted data. Spontaneously reported events of myocarditis and pericarditis were presented for immunocompromised populations for each data source, stratified by age, sex, dose, and time-to-onset (where available). Seriousness of each event was determined according to the ICH E2A definition. Proportional Reporting Ratio (PRR) was calculated.ResultsThere were 178 reports of myocarditis and pericarditis amongst immunocompromised individuals overall. Seriousness was comparable between the immunocompromised and overall populations in both databases. No trends in age or sex were observed amongst immunocompromised individuals. Most reports followed a second vaccine dose and occurred within 14 days. The frequency of reporting was similar to the wider population (PRR=1.36 [95% CI= 0.89-1.82] for VAERS population).ConclusionsMyocarditis and pericarditis following COVID-19 vaccination are very rare, and benefits of COVID-19 vaccination continue to outweigh any perceived risks. Reporting rates of myocarditis and pericarditis were similar in immunocompromised individuals, however defining characteristics differed compared to the whole population; therefore, continued monitoring of adverse events following vaccination remains vital to understand differences between population subgroups.Strengths and Limitations of the StudyThis is the first study to bring together spontaneous reporting data from three regions (Europe, the United States, and the United Kingdom) comparing immunocompromised and immunocompetent populations adverse reactions following COVID-19 mRNA vaccinationSpontaneously reported adverse drug reaction data is known to be subject to underreporting and missing information, including information on comorbidities and concomitant medications.Further biases that may have influenced results, include differences in vaccination strategies between the three regions examined, differences in data collected via spontaneous reporting systems, and the fact that serious events are more likely to be reported.It is not possible to estimate incidence rates using spontaneous reporting data due to a lack of precise denominator data, i.e. the number of people who received the vaccine in the corresponding period.