Recombinant Shingles Vaccine Associated With 9% Lower Cardiovascular Disease Burden Versus Live Vaccine in 72,920 Adults

The study, published in Nature Medicine on 26 August 2024, exploited the 2017-2018 US transition from Zostavax to Shingrix. Researchers compared two cohorts of Medicare beneficiaries who received their first dose in the six months before versus after the switch, tracking incident coronary heart disease, heart failure, ischemic stroke, and atrial fibrillation through claims data. Absolute event rates were not reported; relative burden reductions were 10% for coronary disease, 12% for heart failure, 12% for ischemic stroke in men only, and 7% for atrial fibrillation. No difference was observed for stroke in women.

Prior comparisons of Shingrix versus unvaccinated individuals could not isolate vaccine-specific effects from healthy-user bias. By contrasting two vaccinated populations, the design reduces that bias yet remains susceptible to residual confounding from temporal changes in care or coding. Proposed mechanisms include reduced shingles-related systemic inflammation, particularly lower IL-6 levels, which may slow atherosclerosis progression more rapidly than prevented infections alone would predict.

The CDC already recommends Shingrix for adults 50 and older. These data add a potential cardiovascular rationale but do not alter current indications. A pragmatic randomized trial comparing Shingrix with placebo or another vaccine, powered for major adverse cardiovascular events and measuring inflammatory biomarkers, is required to test causality and quantify absolute risk reduction.

This observational comparison can demonstrate association but cannot establish causation; residual confounding by indication or calendar time remains possible. Confirmation requires a randomized controlled trial with adjudicated cardiovascular endpoints and inflammatory mediator measurements.