Shingles vaccine linked to lower cardiovascular disease risk

A recombinant shingles vaccine reduced the risk of ischaemic heart disease and other cardiovascular conditions by an average of 9 percent among people over 60, ERR reports, citing researchers at the University of Oxford.

Shingles is a painful skin rash that occurs when the virus that causes chickenpox reactivates in nerve endings. Doctors recommend regular shingles vaccination for older people to prevent serious complications.

For many years, vaccination relied on a weakened live vaccine. About a decade ago, a recombinant, artificially produced alternative became available.

A natural experiment

Doctors had previously observed fewer heart conditions among people vaccinated against shingles. However, such observational studies can be biased because people who choose to get vaccinated often take better care of their health in general. This makes it difficult to distinguish the direct effect of the vaccine from the benefits of a healthy lifestyle.

To address this, Oxford researchers used a rare natural experiment in which circumstances created a comparison resembling a clinical trial. The US healthcare system rapidly switched from the live vaccine to the recombinant version at the end of 2017.

This allowed the researchers to compare data from more than 72,000 patients. Some received the old vaccine shortly before the change, while others received the new vaccine immediately afterwards. According to the researchers, this eliminated the statistical bias linked to voluntary vaccination.

The analysis found that people over 60 who received the new vaccine experienced significantly fewer heart problems over the following seven years. Their combined risk of cardiovascular disease fell by 9 percent, with similar protection among men and women.

The effect varied by diagnosis. The risk of ischaemic heart disease fell by 10 percent and the risk of heart failure by 12 percent. Researchers also recorded 7 percent fewer cases of atrial fibrillation among recipients of the new vaccine than in the comparison group. No similar benefit was found for other vascular conditions, such as peripheral artery disease.

There were differences between men and women in stroke prevention. The risk of ischaemic stroke fell by 12 percent among men, while the result was not statistically significant among women. The researchers said this may be because strokes are less common among women in the age group studied, meaning the association requires further research. The risk of ischaemic heart disease, however, fell significantly in both sexes.

Further clinical trials needed

Researchers now want to understand how a vaccine against a skin and nerve disease could also protect the cardiovascular system. They said improved heart health could not be explained solely by preventing shingles, as the difference in shingles incidence between the groups by the midpoint of the study was only half a percent.

The researchers said thorough clinical trials are needed to confirm the findings.