Implications of COVID-19 Vaccination on Hospital Encounters and Outcomes

Adverse events, including cardiac involvement, after vaccination for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been reported. We sought to evaluate trends of hospital encounters for vaccine recipients before and after vaccination. We analyzed patients who received the coronavirus disease 2019 (COVID-19) vaccine in the MedStar Health system (11 hospitals in Washington, District of Columbia and Maryland) from December 2020 through August 2021. We then compared hospital encounters (emergency department visits) of patients 60 days before a vaccine dose and 30 days after a vaccine dose, along with encounters related to the SARS-CoV-2 infection itself. The cohort included 5,217 patients who were vaccinated against COVID-19. Our analysis revealed a total of 6,751 emergency department visits, and we divided this total into 3 cohorts: fully vaccinated (n = 1,779), in vaccination window (n = 1,420), and before vaccination (n = 3,552). We found no significant association between vaccination and rate of presentation for acute coronary syndrome, pericarditis, myocarditis, heart failure, conduction abnormality, or noncardiac conditions. Further, encounters for complications related to SARS-CoV-2 infection decreased significantly from those before vaccination (5.4%) to those in vaccination window (4.2%) to those who were fully vaccinated (1.6%). These findings were consistent when all vaccinated encounters were combined into 1 cohort (fully vaccinated + in vaccination window). In conclusion, our analysis suggests that there is no significant association of COVID-19 vaccination with the rate of hospital encounters for cardiac disease, including acute coronary syndrome, pericarditis, myocarditis, congestive heart failure, and conduction abnormality. Further, administration of the vaccine resulted in a significant decrease in hospital encounters for SARS-CoV-2 infections and associated complications.