Department of Research & Evaluation News

Research conducted at Kaiser Permanente has provided reassurance to the public and lawmakers by refuting claims that COVID-19 vaccines may increase the risk of cardiac-related death.

“Our work reaffirms the previously established safety of COVID-19 vaccines,” said lead author Stanley Xu, PhD, of the Kaiser Permanente Southern California Department of Research & Evaluation.

The study addressed concerns raised by a 2022 analysis released by the Florida Department of Public Health. The analysis suggested an increased risk of cardiac-related death following mRNA COVID-19 vaccination in young men. It was not peer reviewed.

To examine those claims, Dr. Xu and colleagues looked at all deaths in a large group of subjects between December 14, 2020, and August 11, 2021. The subjects were among the millions of members of 8 sites that are part of the Centers for Disease Control and Prevention’s Vaccine Safety Datalink project. The project includes Kaiser Permanente Southern California, Kaiser Permanente Northern California, Kaiser Permanente Colorado, Kaiser Permanente Northwest, and Kaiser Permanente Washington.

The study team applied a modified self-controlled case series design—a statistical strategy that helps to account for the possibility that people who get vaccinated may typically be healthier in general than those who do not.

The analysis showed no increased risk of cardiac-related death among people who received any of the 3 COVID-19 vaccines most commonly used in the United States. Vaccine recipients also had no increased risk of death from any cause, even when setting aside COVID deaths. The findings appeared March 7, 2024, in Vaccine and were presented at the 2023 Vaccine Safety Datalink Annual Meeting.

The study adds to a growing body of COVID-19 vaccine safety research conducted by Dr. Xu and his colleagues. For instance, this year, they presented additional research showing no increased risk of ischemic stroke after COVID-19 vaccination to the CDC’s Advisory Committee on Immunization Practices and to the International Biometric Society.

“Our COVID-19 vaccine safety studies have provided timely and crucial information to policymakers, health care providers, and the public, helping to promote COVID-19 vaccination and address concerns during and after the pandemic,” Dr. Xu said.