A new study published in Nature Medicine reports that adults who predominantly received the recombinant shingles vaccine had a lower risk of cardiovascular events over the following seven years than those who predominantly received the live attenuated vaccine.
A natural experiment from the vaccine switch
Researchers used a natural experiment created by the rapid uptake of the recombinant vaccine and the discontinuation of the live attenuated vaccine after October 2017. They compared adults aged 60 and older who were vaccinated during April to September 2017 with those vaccinated during the same months in 2018, matching 36,460 people in each group.
The study’s primary outcome was a composite cardiovascular endpoint that included ischemic heart disease, ischemic stroke and heart failure. According to the paper, the recombinant-vaccine group had a lower risk of cardiovascular events, with an RMTL ratio of 0.91 and a 95% confidence interval of 0.88 to 0.95.
What the data suggest
The authors report that the lower-risk group spent about 9% more time living free of diagnosis. They also say the association held in both females and males, with no moderation by sex, and remained similar across several sensitivity analyses.
The paper adds that the recombinant vaccine group had lower incidences of the composite endpoint or death, ischemic heart disease and heart failure, while males also had a lower risk of ischemic stroke. The authors note that the results are observational and do not by themselves prove causality.
Why the finding matters
If confirmed in clinical trials and mechanistic studies, the findings could have implications beyond shingles prevention, especially given the global burden of cardiovascular disease. The paper says the observed reduction is clinically meaningful and could translate into large numbers of prevented cases if a true effect is established.
Researchers also note that the biological mechanisms remain unclear. One possible explanation discussed in the paper is that immune and endothelial changes triggered by the vaccine’s adjuvant may have cardioprotective effects, but the authors emphasize that further studies are needed.
For clinicians and public-health teams, the study adds a new layer to the debate around vaccine benefits, suggesting that recombinant shingles vaccination may warrant closer attention not only for protection against shingles, but also for possible broader health effects.
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