U.S, 18 November 2021, Circulation
We examined pericarditis cases from December 15, 2020, to April 15, 2021 seen within Intermountain Healthcare, an integrated healthcare system. Pericarditis was defined by at least two of the following criteria: chest pain, EKG changes, pericardial effusion, and pericardial rub; excluded cases secondary to non-infectious causes (e.g., AF ablation). We determined vaccination within 60 days prior to pericarditis diagnosis using Intermountain and Utah Department of Health vaccination information. Rates of pericarditis per 10 million patient days for vaccinated patients compared to unvaccinated patients were compared. We also examined a case-crossover design with 4 control dates for each pericarditis case.
Results: Of the 29 identified pericarditis cases, 13 (44.8%) had a SARS-Cov-2 vaccination within 60 days before the onset of pericarditis. During the same period, 743,774 individuals in the Intermountain Healthcare system had received at least one dose of the SARS-CoV-2 vaccine. Thus, 1.7 per 100,000 vaccinated individuals were diagnosed with acute pericarditis. Within a 60-day post-vaccination window, the rate of acute pericarditis per 10-million patient-days was 3.90 in the vaccinated group and 0.84 in the unvaccinated group. Thus, there was a 4.49 times higher rate of acute pericarditis in vaccinated patients compared to the unvaccinated individuals (p=0.0002). Case-crossover analysis showed the odds of acute pericarditis was 3.33 higher (95% CI: 1.29, 10.14) in the vaccinated versus the unvaccinated group (p=0.01).