Could Varicella Vaccination Raise Pediatric Stroke Risk?

No evidence of an association between pediatric arterial ischemic stroke (AIS) and varicella vaccination was observed in a recent study.

Several case reports have suggested that varicella vaccination could increase the risk of AIS, but the relationship is controversial.
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In a retrospective population-based cohort study, researchers assessed this risk in children born between January 1, 2006 and December 31, 2013 in Alberta, Canada. Of the 368,992 children, 325,729 were vaccinated between the ages of 11 and 23 months. Hospital discharge data were used to identify children with AIS, and a Cox proportional hazard model assessed the risk of AIS in the 12 months following vaccination.

Overall, the rate of AIS was 7.8 per 100,000 person years at risk in the 12 months following vaccination, compared with 6.8 for children not vaccinated. The adjusted hazard ratio for risk of AIS was 1.6 in vaccinated children compared with non-vaccinated children.

“Our study found no evidence of an increased risk of AIS following varicella vaccination. This population-based cohort study provides reassurance to parents and clinicians regarding the safety of varicella vaccination,” the researchers concluded.

—Michael Potts

Reference:

MacDonald SE, Dover DC, Hill MD, et al. Is varicella vaccination associated with pediatric arterial ischemic stroke? A population-based cohort study. Vaccine. 2018;36(20):2764-2767.