When the varicella-zoster virus becomes active again, it can cause inflammation in blood vessels, which is associated with a higher likelihood of stroke or heart attack.

We analyzed the available evidence and found that 44 studies or assertions support the idea that when the varicella-zoster virus reactivates, it may be linked to inflammation in blood vessels, which in turn is associated with a higher chance of stroke or heart attack. No studies or assertions in our review contradicted this. The varicella-zoster virus is the same virus that causes chickenpox and later shingles. When it reactivates — often decades after the initial infection — it can travel along nerves and trigger inflammation in nearby tissues, including blood vessels. This inflammation may affect how blood flows or how clots form, which could increase the risk of events like stroke or heart attack. The evidence we’ve reviewed so far consistently points to this connection, with all 44 entries aligning with this pattern. We don’t know if the virus directly causes these events, or if other factors like age, immune status, or existing health conditions play a role. But the repeated association across many reports suggests this link is worth paying attention to. If you’ve had shingles, especially if you’re older or have other risk factors for heart or brain health, it may be helpful to talk with your doctor about managing inflammation and cardiovascular risk. Staying up to date on vaccines, like the shingles vaccine, could be one way to reduce reactivation — but always follow medical advice tailored to your situation.