The drugs activate the latent herpes zoster virus and increase the risk around 18 per cent compared to someone not taking the drug.
The drugs affect the immune response—and the regulation of T-cells in particular—which makes the reactivation of the virus more likely, say Chinese researchers.
A research team from Wenzhou Medical University reviewed previously-published medical studies that involved more than 2 million people. The researchers weren't sure if the statins had a direct effect, or whether LDL cholesterol—the so-called 'bad' cholesterol that the statins target—had a protective effect and reduced the risk of viral reactivation. So, in reducing cholesterol levels, statins could inadvertently be raising the risk of shingles.
Another possibility, the researchers say, is linked to the recent discovery that statins can cause diabetes—and shingles is far more common in diabetics.