Herpes zoster vaccination was associated with an 18% reduction in cardiovascular events among adults aged 18 years and older and a 16% reduction among adults aged 50 years and older, according to findings from the first global systematic literature review and meta-analysis examining this association.

The research, presented at the 2025 European Society of Cardiology Congress, analyzed 19 studies and found that both recombinant herpes zoster vaccine and live attenuated zoster vaccine demonstrated statistically significant differences with lower risks of stroke and heart attack compared with no herpes zoster vaccination. In studies reporting cardiovascular event absolute risk, the absolute rate difference ranged from 1.2 to 2.2 fewer events per 1,000 person-years.

Study Methodology and Scope

The global systematic literature review utilized three scientific literature databases, with meta-analysis inclusion criteria following Cochrane guidelines. Of the 19 studies included in the review, eight observational studies and one randomized controlled trial consisting of a pooled safety analysis of two phase 3 randomized trials met meta-analysis inclusion criteria for herpes zoster vaccination effectiveness on cardiovascular events. 

Across all nine studies, 53.3% of participants were male, with seven studies reporting mean ages ranging from 53.6 years to 74 years old. The randomized controlled trial was not designed or powered to evaluate the effects of herpes zoster vaccination against cardiovascular events.

Principal Findings and Clinical Implications

"We looked at the currently available evidence, and found that in this analysis, vaccination against herpes zoster was associated with a lower risk of cardiovascular events, such as heart attacks or strokes," said study author Charles Williams, MD, of GSK Global Medical Affairs – Vaccines. "Further research studies are now needed to find out whether this association can be attributed to an effect of herpes zoster vaccination."

Both vaccine types—recombinant herpes zoster vaccine and live attenuated zoster vaccine—demonstrated comparable protective associations across the analyzed age groups.

Study Limitations and Research Gaps

"While our findings are encouraging, there are some limitations to the available data that we studied," explained Dr Williams. "Almost all the evidence came from observational studies, which are prone to bias and shouldn't be used to infer causality. All the studies used in the meta-analysis aimed primarily to investigate the use of herpes zoster vaccine to prevent shingles in the general population, which may limit the ability to generalize this research to people with a higher risk of cardiovascular events. This demonstrates the need for more research in this area."

The predominance of observational studies represents a limitation, as such designs cannot establish causality between vaccination and cardiovascular outcomes. The primary endpoints of included studies focused on shingles prevention rather than cardiovascular protection, potentially limiting generalizability to high-risk cardiovascular populations.

The recent 2025 European Society of Cardiology clinical consensus statement on vaccination as a new form of cardiovascular disease prevention states that vaccines should be considered as the fourth pillar of medical cardiovascular disease prevention alongside antihypertensives, lipid-lowering drugs, and medications that treat diabetes.

Research Funding and Disclosures

This research was industry funded by GSK. Dr Williams is employed by GSK. The study findings were presented during the Risk Factors and Prevention session at the 2025 European Society of Cardiology Congress in Madrid, Spain.

Source: ESC Press Office