Pfizer COVID19 vaccine is not associated with acute cardiovascular events

BACKGROUND: Previous reports on acute cardiovascular events and sudden death following administration of COVID19 vaccines usually reported no association, but this issue still stirs much ado. We aimed to assess the risk for acute cardiovascular events that require hospitalization in the short-term following administration of the second Pfizer COVID19 vaccine dose in Israel. METHODS: We have used a self-controlled case series (SCCS) study design, and included second-dose vaccinees in the period from Jan 11th, 2021 to Oct 31st 2021, who had not been diagnosed with COVID19 and who had an acute cardiovascular event (acute myocardial infarction or acute stroke or acute thromboembolic event; myocarditis events excluded) that required hospitalization in the 60 days following vaccine administration. National databases (COVID19 vaccines; COVID19 infection; Hospitalizations) were used to assemble the study population. The first 30 days were defined ‘high risk period’ while the next 31-60 days were defined ‘control period’, and the risk for an acute cardiovascular event was compared between these periods using a conditional logistic regression model. Possible moderators such as: sex, age group and seasonality were included. RESULTS: Out of 5,700,112 second-dose vaccinees in the defined time period, 4,163 had an acute cardiovascular event in the 60 days following vaccine administration: 1,979 in the ‘risk period’ and 2,078 in the ‘control period’ (Odds ratio, OR = 0.95, 95% confidence interval, CI 0.90-1.01, p = 0.12). Moderation of sex, age group and recent (less than 60d prior to vaccination) acute cardiovascular event were not significant. A sensitivity analyses looking at 100 days of follow-up post-vaccination did not change these results. CONCLUSIONS: We found no indication for an increased risk for an acute cardiovascular event in the 30 days (compared to 31-60 days) following administration of the second vaccine dose of Pfizer COVID19 vaccine. KEY MESSAGES: • We found no indication for an increased risk for an acute cardiovascular event in the 30 days (compared to 31-60 days) following administration of the second vaccine dose of Pfizer COVID19 vaccine. • These findings did not change when sensitivity analyses were used.