Risk of heart problems decreases with successive COVID-19 vaccine doses

6th March 2023
Image of heart


The risk of suffering a heart problem decreases in proportion to the number of COVID-19 vaccine doses a person receives, according to a new analysis by a team of researchers from Imperial College London, the universities of Cambridge, Edinburgh and Swansea, and Health Data Research UK.

It is now well established that COVID-19 is associated with a higher risk of cardiovascular problems in the general population. Previous studies have shown that people with COVID-19 have a higher risk of arterial thrombosis and venous thromboembolism, compared with people without COVID-19, and that this risk lessened over time. Other studies have found that people who were hospitalised with COVID-19 had a higher risk of heart failure, stroke, ischemic heart disease, and venous thromboembolism, compared with people who did not have COVID-19.

However, misinformation spread online and in the media has increased concern among some about risks to the heart posed by the COVID-19 vaccines. While there have been rare cases of myocarditis (inflammation of the heart muscle) following the Moderna and (even more rarely) Pfizer vaccines, COVID-19 itself is much more likely than the vaccine to cause myocarditis, and people who are vaccinated have a much lower risk of experiencing other serious complications caused by COVID-19.

Research suggests that overall, myocarditis is no more likely to be triggered by a COVID-19 vaccine than by any other vaccine. More information is available on the British Heart Foundation website.

People with chronic respiratory diseases such as asthma, chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis and pulmonary fibrosis are at increased risk of cardiovascular disease regardless of COVID-19.

In this study, the researchers set out to investigate the association between pre-existing chronic respiratory disease and risk of cardiovascular events following COVID-19, using routinely collected data from more than 3.5 million people in England. They also looked at the impact on cardiovascular outcomes of hospitalisation with COVID-19, and of vaccine doses. Their results were published as a preprint on MedRxiv (meaning they have not yet been peer reviewed).

Their findings showed that, overall, people with pre-existing respiratory disease had a slightly higher risk of cardiovascular events, heart failure, and pulmonary embolism following infection with COVID-19, compared with those without pre-existing respiratory disease.

However, this risk differed according to whether a person was hospitalised for COVID-19. In those with pre-existing chronic respiratory disease who were not hospitalised, there was a higher risk of heart failure and pulmonary embolism compared with people without pre-existing respiratory disease. However, in those who were hospitalised with COVID-19, there was a reduced risk of stroke, and a similar risk of all other cardiovascular outcomes. This could be due to better monitoring of people with pre-existing chronic disease in hospital.

Regardless of pre-existing respiratory disease, the risk of cardiovascular problems was lower in people who were vaccinated, and lowest of all in those who had received a booster dose.