Stroke risk increased after chickenpox in children

October 9, 2013

Within the first 6 months after chickenpox, there was a significant increased risk for stroke among children, according to researchers from the London School of Hygiene & Tropical Medicine.

“Cases of childhood [arterial ischemic stroke] or transient ischemic attack (TIA) occurring in the months after chickenpox (primarily VZV infection) have been thought to represent a vasculitis, resulting either from direct viral invasion or as a post-infectious phenomenon,” the researchers wrote in Clinical Infectious Diseases. “Cases of [arterial ischemic stroke] following chickenpox have also been reported in adults and the purported effect may not be restricted to children.”

The researchers used electronic health records from four databases in the United Kingdom with more than 100 million person-years of observation. They identified those with chickenpox and a stroke or TIA. They evaluated the risk for stroke or TIA in the 0- to 6-month time frame and the 7- to 12-month time frame after chickenpox.

The study included 560 patients, including 60 children, who had a stroke or TIA after chickenpox. Among children, there was a fourfold increased risk for stroke 0 to 6 months after chickenpox, but not 7 to 12 months after chickenpox. Among adults, there was a less marked risk for stroke 0 to 6 months after chickenpox. There was no increased risk for TIA in either group.

“The fourfold increased risk we identified will represent only a small absolute stroke risk, given the low baseline incidence of pediatric stroke,” the researchers wrote. “Our findings suggest that the renewed attention on the mechanisms by which VZV and other infections cause vascular injury is warranted and could identify strategies to prevent strokes.”