A newer shingles vaccine may offer benefits that extend beyond preventing a painful rash, with fresh research linking it to a lower burden of cardiovascular disease than the older live shingles vaccine.

The findings, published in Nature Medicine recently, add to growing interest in the relationship between infection, inflammation and heart health.

Researchers found that older adults who received the recombinant shingles vaccine, known as Shingrix, experienced a 9% lower overall burden of cardiovascular disease during seven years of follow-up than people who received the previous live vaccine, Zostavax.

The study does not establish that Shingrix directly prevents heart disease. It was observational, meaning researchers examined health outcomes in groups who had already received different vaccines. Such studies can identify important associations, though they cannot rule out every possible difference between the groups being compared.

Even so, the results are notable.

Heart disease, heart failure, stroke and atrial fibrillation remain among the leading causes of illness, disability and death in older adults. A vaccine primarily intended to prevent shingles could, if further evidence supports the finding, have wider implications for preventive care.

“Shingrix is given as two doses, generally separated by two to six months. It has been shown to provide around 90% protection against shingles”

Shingles is caused by reactivation of the varicella-zoster virus, the same virus responsible for chickenpox. After chickenpox resolves, the virus does not necessarily leave the body. It can remain dormant in nerve cells for decades, then reactivate later in life. The result can be shingles, a blistering and often intensely painful rash. In some people, pain persists long after the rash has healed, a complication called post-herpetic neuralgia.

Risk rises sharply with age. It is also higher among people whose immune systems are weakened by illness or treatment. The illness can affect the eyes, ears or nervous system in serious cases. It may trigger substantial inflammation throughout the body.

The new analysis examined cardiovascular outcomes in 72,920 adults aged 60 years and above. Roughly half received the live shingles vaccine between April and September 2017, shortly before the United States shifted towards use of the recombinant vaccine. The remaining participants were vaccinated between April and September 2018, when Shingrix had become the dominant option.

This timing created a useful natural comparison between people vaccinated in two adjacent periods, before and after the national transition. Zostavax was later discontinued in the United States in 2020. Shingrix is now the standard shingles vaccine in the country and in many other major markets.

Compared with people who received the older vaccine, those given Shingrix had lower burdens across several major cardiovascular outcomes.

The study reported a 10% lower burden of coronary heart disease and a 12% lower burden of heart failure. There was also a 7% lower burden of atrial fibrillation, a common abnormal heart rhythm that can raise the risk of stroke and heart failure. For ischaemic stroke, the analysis found a 12% lower burden among men who had received Shingrix.

No statistically significant association was observed among women for this particular outcome. Researchers will need to investigate whether that difference reflects biological variation, chance, differences in underlying risk, or other factors.

The broad pattern is biologically plausible, according to cardiology experts who reviewed the findings. Shingles can provoke a marked inflammatory response. Inflammation is increasingly recognised as a key part of cardiovascular disease, alongside well-established contributors such as high blood pressure, high cholesterol, diabetes, smoking and obesity.

Atherosclerosis, the narrowing and hardening of arteries caused by fatty plaque build-up, is not merely a mechanical problem. It is also an inflammatory process. Infections may add stress to the immune and cardiovascular systems, potentially destabilising existing plaque or increasing the likelihood of clot-related events in vulnerable people.

Preventing shingles may therefore reduce episodes of acute inflammation that could affect the heart and blood vessels. Experts have also pointed to changes in inflammatory markers, including interleukin-6, or IL-6, as one possible explanation for the observed differences. IL-6 is involved in immune signalling and has been linked with cardiovascular risk in previous research.

There is another possibility. The recombinant vaccine itself may produce immune effects that differ from those of the older live vaccine. Shingrix contains an engineered viral protein combined with an adjuvant, an ingredient designed to strengthen the immune response.

Zostavax used a weakened live virus. The distinct technologies may influence how effectively the vaccines prevent viral reactivation and how they interact with inflammatory pathways.

That remains a theory, not a settled conclusion.

The gap in protection against shingles is already well established. Shingrix is given as two doses, generally separated by two to six months. It has been shown to provide around 90% protection against shingles, with strong effectiveness maintained over time. Zostavax was given as a single dose and offered approximately 50% to 60% protection, with its effectiveness declining as years passed.

Those differences matter because shingles itself has been associated in earlier research with an increased risk of vascular complications, particularly stroke. If a more effective vaccine prevents more episodes of shingles, it could plausibly reduce some of the downstream cardiovascular consequences linked to viral reactivation.

Still, the new study should not be interpreted as evidence that a shingles vaccination can replace standard heart disease prevention. It cannot substitute for controlling blood pressure, managing cholesterol, treating diabetes, avoiding tobacco, staying physically active, eating a balanced diet and seeking medical care for symptoms such as chest pain, breathlessness or palpitations.

Nor does a 9% reduction mean that every vaccinated individual has a 9% lower personal risk of every cardiovascular event. The figure describes the relative difference in the overall cardiovascular disease burden observed between the two study groups. Individual risk depends on many factors, including age, sex, family history, existing heart disease, medication use, social circumstances and access to healthcare.

The research also compared two vaccinated groups rather than vaccinated people with unvaccinated people. This is an important strength in one respect, it reduces some of the “healthy vaccinee” effect, where people who choose vaccination may differ from people who do not in ways that influence health outcomes. Both groups had taken up shingles vaccination, which makes the comparison more focused.

Yet limitations remain. Patterns of healthcare use may have changed. Cardiovascular treatments may have evolved. The analysis may not capture every relevant lifestyle or clinical variable. The researchers adjusted for known factors, but adjustment cannot eliminate all uncertainty.

Further studies will be needed. Ideally, investigators will test whether similar findings appear in other populations, healthcare systems and age groups. Research should also explore why the association appeared stronger for some conditions than others, and why the ischaemic stroke finding differed by sex. Studies examining inflammatory markers before and after vaccination could help clarify the possible biological pathway.

The findings arrive at a time when adult immunisation is being viewed more broadly. Vaccines have traditionally been judged by whether they prevent a specific infection or reduce its severity.

Increasingly, researchers are investigating whether avoiding infections may also prevent complications elsewhere in the body. Influenza vaccination, for example, has been studied for possible cardiovascular benefits in people with heart disease. The new shingles research contributes to that larger conversation.

Current United States public health guidance recommends Shingrix for all adults aged 50 years and older. The same recommendation applies in Malaysia. It is also recommended for adults aged 19 years and over who are immunocompromised or expected to become immunocompromised because of a disease or treatment. People who previously received Zostavax may still be advised to receive Shingrix, depending on local recommendations and their clinical circumstances.

For most people, the primary reason to receive the vaccine remains clear, preventing shingles and its potentially debilitating complications. The possibility of additional cardiovascular benefit is encouraging, though it should be considered preliminary.

The study offers a timely reminder that infectious diseases and chronic illnesses are not always separate problems. The immune system, blood vessels and heart are closely connected. Protecting against one condition may sometimes influence another.

For now, the evidence supports vaccination as an effective way to reduce the risk of shingles. Whether it also becomes a recognised tool in cardiovascular prevention will depend on what future research finds.