Shingles vaccine reduces risk of heart disease by 23%, study of one million people finds

Getting the shingles vaccine could do more than just prevent a painful red rash — it may also lower the risk of heart disease and stroke, according to a new South Korean study of more than one million people published in the European Heart Journal. The highly common herpes strain, also called varicella-zoster virus (VZV), can cause chickenpox in childhood and later develop into shingles in older or immuno-compromised adults. The shingles vaccine is already considered a top-line defense against the virus, but recent studies have pointed to other unexpected health benefits. An analysis of health outcomes for 1,271,922 people age 50 and older found a 23% lower risk of cardiovascular disease among those who were vaccinated for shingles. The reduced risk was most noticeable up to eight years after vaccination among males, people under 60, and even those with “unhealthy lifestyles,” such as chronic smoking or drinking, according to the May 6 study. “Since shingles can cause inflammation in blood vessels and lead to blood clots, which in turn raise the risk of heart disease, preventing shingles through vaccination might also help reduce these cardiovascular risks,” explained Hayeon Lee, a coauthor and researcher from the Lee Kyung Hee University College of Medicine in an email. It’s also possible that the nerve damage caused by shingles could disturb the heart’s rhythm, leading to irregular palpitations and even cardiac arrest, per the study. The vaccine may be better at preventing shingles in younger patients and males because of their more robust immune systems, Lee said. “If a vaccine helps lower the risk of both infection and serious chronic conditions, it becomes an even more valuable public health tool,” Lee said. “This study supports a broader understanding of vaccination — not just as a shield against infectious diseases, but as part of a more comprehensive approach to maintaining long-term health.” More research is needed to determine a direct causal link between vaccination and reduced cardiovascular event risk, but this analysis is the largest and most comprehensive so far, presenting a compelling case for those on the fence about vaccination, said Dr. Sharon Curhan, a physician and epidemiologist at Brigham and Women’s Hospital, who was not involved in the study. Since this herpes strain can lie dormant in the body for years after exposure before it reactivates into shingles, you don’t need a history of chickenpox to get the vaccine, Curhan said. In fact, more than 99% of adults age 50 years and older worldwide have been exposed to VZV, and many may not have had, or known they had chickenpox at all, according to estimates from the US Centers for Disease Control and Prevention. The limitations Patients from the study used an older variation of the shingles vaccine that is being phased out of most countries. The live zoster vaccine, no longer available in the US as of 2020, contains a living but weakened form of the virus used to generate an immune response. It’s since been swapped for Shingrix, a two-shot recombinant zoster vaccine containing only part of the virus — which has shown to be more effective. More research is needed to compare the various health benefits of these different vaccine variations, said Dr. Pascal Geldsetzer, an assistant professor of medicine at Stanford University who was not involved in the study. “The biggest limitation of this type of research is that you’re essentially comparing people who get vaccinated to those who don’t get vaccinated,” Geldsetzer said. “We know that those people who decide to get vaccinated are often very different from those who don’t in their health motivations and behaviors.” Researchers were able to sort for several demographic variables such as age, sex, income level and pre-existing conditions like high blood pressure, diabetes and high cholesterol. They also considered the frequency of medical visits and use of specific medications based on national insurance records, Lee said. Still, some variables, like diet, other vaccinations, and proper adherence to treatments, can always slip through the cracks in non-clinical trials which use large data sets like the one used in this study, Geldsetzer said. For this reason, he hopes future studies can be randomized and use data from a clinical setting. Additionally, Lee said future research should observe more racially and ethnically diverse populations, as immune responses can vary across different populations. Other benefits of the shingles vaccine These findings follow several other studies identifying the possible health benefits of shingles vaccination. In April, Geldsetzer and a team of researchers from Stanford published a study that found people who received the vaccine had a 20% reduced risk of dementia compared with those who didn’t get it. This study took advantage of a “natural experiment” after Wales rolled out its shingles vaccination program in 2013. Due to limited vaccine supply, government officials decided that only Welsh adults born on or after a very specific date would be eligible, so researchers could directly compare the health outcomes of two groups of individuals over time while limiting covariables. This is likely because shingles doesn’t just cause inflammation in the blood vessels, said Geldsetzer. It also inflames nerves throughout the body, which can lead to long-lasting pain disorders and, in the case of dementia, brain tissue damage.