Veterans Study Finds Covid Vaccine Linked to 38% Lower Risk of Major Heart Events but Notes Low Uptake

A study published June 15, 2026, in JAMA Internal Medicine found that veterans who received a Covid vaccine in addition to a flu shot had a roughly 38% lower risk of Covid-associated major cardiovascular events in the following eight months. The analysis followed more than 1 million veterans who received flu vaccinations at Veterans Affairs facilities in 2024.

About one-third of them also received a Covid vaccine.

The reduction was greatest among veterans aged 75 and older and those with chronic kidney or lung disease. Covid vaccination was also associated with a nearly 24% reduction in all-cause cardiac events, including events without a documented Covid diagnosis.

The authors estimated that the observed risk reductions could translate to prevention of approximately 3,500 major cardiac events and 2,400 deaths annually per 1 million people.

Ziyad Al-Aly, a doctor and clinical researcher at Washington University in St. Louis who led the study, said unrecognized Covid infections likely contributed to the cardiac events. “What that really means is that those [events] are actually likely related to SARS-CoV-2, that were never recognized to be so in the first place,” he said.

Robert Califf, a cardiologist and former FDA commissioner, wrote an accompanying commentary. “There are many, many studies now that show that vaccinations of various types seem to reduce the risk of chronic diseases, including cardiovascular disease … this is not inconsistent with what the other studies have shown,” Califf stated. Califf also noted that testing practices have changed.

“It’s also worth keeping in mind that the testing environment has changed a lot, so knowing for sure who had a subsequent infection, that’s probably the shakiest of the whole thing,” he said. A separate study led by Ryan Wiegand and CDC researchers, also published in JAMA Internal Medicine, evaluated the effectiveness of 2024-2025 Covid vaccines.