According to a study released on Aug. 26, 2026, the recombinant shingles vaccine was linked to a lower cardiovascular disease burden over a seven‑year period compared with the discontinued live‑virus version, suggesting a potential added benefit beyond shingles prevention.
Heart disease remains the leading cause of death in the United States, prompting insurers and clinicians to seek cost‑effective interventions. Shingles, caused by reactivation of the chickenpox virus, primarily affects seniors and can be prevented by vaccination.
The national immunization program switched from the live attenuated product, Zostavax, to the newer recombinant formulation in late 2017. Zostavax was removed from the market in 2020, leaving the recombinant option as the sole shingles vaccine available.
Fabiana Corsi‑Zuelli, a psychiatrist at the University of Oxford, led the analysis that examined cardiovascular outcomes among older adults who received either vaccine.
Study design avoids bias
Earlier investigations compared vaccinated individuals with those who remained unvaccinated, a method vulnerable to “healthy‑vaccinee bias.” People who seek vaccines often differ in health habits that also affect heart risk.
To sidestep that issue, the researchers treated the 2017 vaccine transition as a natural experiment. They noted that those who received a dose in early 2018 were almost always given the recombinant product (93.5% of doses), whereas the same calendar window in 2017 saw 98.6% live‑virus shots.
Data were drawn from the TriNetX US Collaborative Network, encompassing roughly 60 health‑care organizations. The team matched 36,460 adults aged 60 or older who were vaccinated in 2018 with an equal number from 2017, aligning them on 83 demographic and clinical variables.
People with blood cancers, immune deficiencies or recent immunosuppressive therapy were excluded. The primary endpoint tracked cardiovascular diagnoses for up to seven years using a restricted mean time lost ratio, which measures average delay before disease onset.
Key findings on heart disease
The analysis showed a 9% lower composite cardiovascular burden among recipients of the recombinant vaccine. The advantage was driven mainly by a 10% reduction in ischemic heart disease and a 12% drop in heart‑failure diagnoses, effects that appeared in both men and women.
Ischemic stroke incidence fell by 12% in men but did not differ significantly among women or the overall cohort. A secondary outcome revealed a 7% lower burden of atrial fibrillation, while rates of myocardial infarction with complete blockage, myocarditis, peripheral artery disease, and various stroke subtypes showed no meaningful change.
The protective signal was strongest during the first 3.5 years after vaccination and waned in the latter half of follow‑up. Supporting analyses that accounted for competing mortality risk and excluded the COVID‑19 pandemic period produced consistent results.
Possible mechanisms and implications
The authors noted that the adjuvant AS01, present in the recombinant vaccine, has been associated in other studies with lasting modifications to immune‑cell activity, including reduced interleukin‑6 signaling—a pathway linked separately to cardiovascular risk.
“The biological mechanisms underlying these observations remain to be clarified experimentally,” the report stated, emphasizing that the effect could not be fully explained by the vaccine’s superior shingles prevention, given the smaller difference in shingles cases between groups.
From a public‑health standpoint, if the observed association holds up in randomized trials, the findings could reshape how insurers evaluate the value of shingles vaccination for seniors, potentially adding cardiovascular protection to the known benefits.
Limitations and next steps
Relying on electronic health‑record data introduces uncertainties: undiagnosed conditions may be missed, and the records lack detailed socioeconomic and lifestyle factors such as smoking or diet, which could differ between cohorts.
The study is observational, not a randomized controlled trial, so it demonstrates correlation rather than causation. Additionally, the design presumes that the live‑virus vaccine had no independent cardiovascular effect—a premise the authors could not directly test.
Nevertheless, the investigators argue that the results justify clinical trials and mechanistic research to explore any cardioprotective properties of shingles vaccines, noting the global burden of cardiovascular disease and the potential public‑health impact if the association proves causal.
The findings merit further investigation.
