A shingles vaccine was linked to lower risks of heart attack, heart failure and stroke in older adults, a US study of 70,000 people suggests.
People who received Shingrix had a 12 per cent lower risk of a cardiovascular event during the first three and a half years after vaccination.
By the end of the seven-year follow-up, vaccination was associated with a 4 per cent lower risk of cardiovascular disease.
Dr Maxime Taquet, a clinical lecturer at the University of Oxford who led the study, said: “If confirmed in clinical trials, vaccinating older adults against shingles could prevent hundreds of thousands of coronary heart diseases, strokes and cases of heart failure worldwide, making it one of the most impactful interventions we could offer to protect both the brain and the heart in later life. The effect might be enormous.”
Researchers tracked health records from 70,000 US adults aged 60 and over who received shingles vaccination, involving an initial dose and a booster.
The study compared rates of cardiovascular disease among people vaccinated before and after the rapid US switch in 2017 from Zostavax, an older vaccine based on a weakened version of the chickenpox virus, to Shingrix.
Previous studies had compared vaccinated and unvaccinated people, which researchers said could leave the findings open to distortion because of differences between the two groups.
Shingles is caused by the reactivation of the chickenpox virus, which remains dormant in the body after an earlier infection. It can cause a painful rash and nerve pain that may persist for months or years after the rash clears, a complication known as post-herpetic neuralgia.
Zostavax became available in 2006 and was later succeeded by the more effective Shingrix vaccine, which uses newer vaccine technology. In the UK, Shingrix is offered to everyone over 65.
Researchers said that if the cardiovascular findings are confirmed in a randomised controlled trial, in which participants are randomly assigned treatments to test their effects, the benefit could be comparable with blood pressure-lowering medication.
“If confirmed in a [randomised controlled trial], the effect of Shingrix would be equivalent to antihypertensives,” Taquet said.
Several trials are under way to provide more definitive evidence.
Researchers are also investigating why the vaccine may be associated with cardiovascular protection. One possibility is that shingles increases the risk of heart and vascular diseases, meaning the more effective vaccine reduces that risk.
Another possibility is that the vaccine has broader effects on the immune system that suppress inflammatory proteins.
Dr Hugo Pedder, a research fellow in statistical modelling at the University of Bristol who was not involved in the research, said: “A randomised trial would be the best way to confidently answer whether recombinant vaccines do provide the benefits seen here versus live vaccines, but until such a trial is done this study provides some of the best-quality observational evidence supporting an effect of recombinant v live vaccines for cardiovascular outcomes.”
