COVID Vaccines Reduce Risk of Heart Failure, Clots

3 min read

March 18, 2024 – By now, most of us have heard the benefits of getting a COVID-19 vaccine, like the reduced risk of serious illness should you get a COVID infection and a significantly lowered chance of hospitalization or death should you get sick. Now, there may be another benefit to add: Getting a COVID shot may also help reduce the risk of heart failure. 

That's according to researchers from the University of Oxford in England, who found that people who got COVID-19 vaccines had a reduced risk of heart failure, compared to people who didn’t get vaccinated. 

The protection lasted up to a year and also lowered the chance of experiencing heart inflammation and some types of blood clots. The findings were published this month by the journal Heart

The authors suggested that their large study provides another look at what they called the “tangled” relationship between COVID and the risk of heart and blood clot problems. Previous research on the topics has provided complex findings on the relationship between vaccination and the risk levels of those conditions.

The new findings suggest that the protection against heart and blood-flow problems associated with vaccination outweighs the risks. That’s because a COVID infection creates a risk level for those same heart and blood clot problems that is significantly higher than the risk just from vaccination. Ultimately, vaccinated people in the study who got COVID were less likely to have severe symptoms, less likely to be hospitalized, and less likely to die.

“Our findings probably reflect the fact that the vaccines are effective in reducing infection, and minimize the risk of severe COVID-19. These results could encourage COVID-19 vaccination among hesitant people who are worried about the potential risk of vaccine side effects,” said lead study author Nuria Mercade Besora in a statement published by the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences at the University of Oxford.

Researchers analyzed health data for more than 20 million people living in the United Kingdom, Spain, and Estonia. About half of the people were vaccinated with shots made by BioNTech/Pfizer, Moderna, AstraZeneca, or Janssen/Johnson & Johnson.

Protection against heart and blood flow problems was strongest during the first 30 days after infection with the virus that causes COVID. The researchers found that the risk of heart failure among vaccinated people was reduced by 55% during the initial days of an infection, and by at least 50% during the year following, compared to unvaccinated people. Venous thromboembolism risk, which is when a clot forms in a vein, was reduced by 78% during an initial infection and by at least 50% in the year following. The risk of clots that affect blood flow in the arteries was reduced by 47% during the initial days of an infection and by at least 48% during the year afterward.

The authors wrote that further follow-up is needed, particularly to look at the effects of COVID booster shots that were given after the period for their study, which began in 2021.