The Comparison That Makes This Study Different
Adults who received the current shingles vaccine were 10 percent less likely to be diagnosed with heart disease over seven years than adults who received the older shingles vaccine it replaced, according to research published in Nature Medicine. The same analysis found a 12 percent lower likelihood of a heart failure diagnosis, and a 12 percent lower stroke risk in men.
The design choice behind those numbers is the reason they deserve attention. Most earlier work suggesting a heart benefit from shingles vaccination compared vaccinated people with unvaccinated people, and people who choose to get vaccinated tend to be healthier to begin with. Study co-author Maxime Taquet, a psychiatrist at the University of Oxford who has previously studied the shingles vaccine and dementia risk, told Nature that “this is a very biased way of answering the question.”
Instead, his team compared two vaccinated groups. Both had opted in. Both had walked into a clinic. The main difference was which vaccine was available at the time.
The study drew on TriNetX, a database of electronic health records from health systems across the United States. Researchers compared two groups of more than 36,000 people each, all aged 60 and older, for a combined total of more than 70,000. One group received Shingrix, the recombinant vaccine that pairs a viral surface protein with an immune-boosting compound. The other received Zostavax, a now-discontinued vaccine containing a weakened live form of the virus.
Shingrix replaced Zostavax in the United States after October 2017, providing researchers with what they call a natural experiment. People vaccinated in the months just before and just after that switch were broadly similar to one another, but received different products.
The team tracked heart disease, heart failure, and stroke for seven years after vaccination, focusing on disease burden, meaning the amount of time a person spent living with a diagnosed cardiovascular condition. On that measure, Shingrix recipients spent, on average, 9 percent more time free of cardiovascular disease across the seven-year window.
Shingles is caused by the varicella-zoster virus reactivating in the body, most often in people over 50. It is the same virus responsible for chickenpox.
The Limits Doctors Are Naming Out Loud
This is an observational study built from medical records, not a randomized trial, and the researchers and outside experts have both said so plainly.
Emily Rayens, an epidemiologist who specializes in vaccine development at Kaiser Permanente in Pasadena, California, and who was not involved in the work, called the findings particularly exciting and more robust than earlier research on the heart-protection effects of shingles vaccination. She also said the work cannot settle the central question, telling Nature: “We cannot definitively conclude that there is a causal link.”
That distinction is not a technicality. An association means the two groups differed on an outcome. It does not establish that the vaccine produced the difference. Residual differences between people vaccinated before and after the 2017 switch could still explain part of the gap, and electronic health records capture diagnoses rather than the underlying biology.
The database itself has a blind spot worth naming. As STAT reported, TriNetX draws on roughly 60 health systems but excludes people covered by public health insurance, leaving out a large share of Americans over 65.
Disclosure matters here too. Taquet consults for GSK, which manufactures Shingrix, though he has said the company was not involved in the study, according to Science. The same report notes that the apparent protection was strongest in the earlier years after vaccination and narrowed over the full seven-year window.
The effect sizes are also modest. A 10 percent relative reduction in heart disease diagnoses is meaningful across a large population but is not the same as a 10 percent reduction in any individual’s personal risk, which depends heavily on blood pressure, cholesterol, smoking, diabetes and family history.
Current medical guidance has not changed based on this study, and nobody should treat a shingles vaccine as a substitute for cardiovascular care.
The Practical Question for Adults Over 50
For most readers, this research does not create a new decision. It adds context to one that already exists.
The CDC already recommends two doses of the recombinant shingles vaccine for adults 50 and older and for adults 19 and older with weakened immune systems, primarily to prevent shingles and its most common complication, long-lasting nerve pain. Zostavax is no longer distributed in the United States, so the comparison group in this study is historical. Nobody is currently choosing between the two products.
What the findings may reasonably change is the weight of the conversation. An adult who has been putting off the two-dose series because shingles seemed like a manageable rash now has an additional consideration to raise with a clinician or pharmacist, particularly if they already carry cardiovascular risk factors.
Cost is usually the more practical barrier. The vaccine is covered without cost sharing for most people with Medicare Part D and for most commercial plans that follow federal preventive coverage rules, though coverage details vary and people on Medicare Advantage or without insurance should confirm before booking. Anyone facing an out-of-pocket charge can ask a pharmacist about pricing differences between pharmacies and about manufacturer assistance programs.
People who are pregnant, currently ill with a fever, or who have had a serious allergic reaction to a previous dose should discuss timing with a clinician first. Temporary side effects, including a sore arm, fatigue, headache, and a short-lived fever, are common after the second dose and are not a reason to skip it.
Where the Evidence Goes Next
The most important remaining gap is that no randomized controlled trial has yet tested whether the recombinant shingles vaccine prevents cardiovascular events. Until one reports, the honest description of the evidence is a consistent, now better-controlled association rather than a demonstrated benefit.
Several earlier observational studies, along with separate work on influenza vaccination and cardiovascular disease, have pointed in the same direction, which is part of why researchers describe the evidence as mounting rather than settled. Researchers have floated the vaccine’s adjuvant, an added compound not present in Zostavax, as one possible explanation, but whether the mechanism involves reduced inflammation, avoided shingles episodes, or something else entirely remains unresolved.
Readers should expect follow-up analyses attempting to replicate the finding in other health record systems, and should treat any coverage claiming the vaccine prevents heart attacks as running ahead of the data. The reasonable step today is a conversation about shingles protection itself, with the cardiovascular signal as supporting context rather than the reason.
Key Questions Answered
What did the study find? Adults 60 and older who received Shingrix had 10 percent fewer heart disease diagnoses, 12 percent fewer heart failure diagnoses, and 9 percent more time free of cardiovascular disease over seven years than adults who received Zostavax.
Does this prove the vaccine protects the heart? No. This was an observational study using medical records. An independent expert quoted by Nature said a causal link cannot be definitively concluded.
Why compare two vaccines instead of vaccinated versus unvaccinated people? Because people who choose vaccination tend to be healthier, which can inflate apparent benefits. Comparing two vaccinated groups reduces that bias.
Are there conflicts of interest to weigh? One study co-author consults for GSK, which makes Shingrix, though he says the company was not involved in the research.
Should anyone get vaccinated specifically for heart protection? No. Current guidance recommends the shingles vaccine to prevent shingles and its complications. Cardiovascular findings are supporting context, not a separate indication.
Who is recommended to get the shingles vaccine? CDC recommends two doses for adults 50 and older, and for adults 19 and older with weakened immune systems. A clinician or pharmacist can confirm individual eligibility.
What would settle the question? A randomized controlled trial directly testing cardiovascular outcomes. None has reported results.
