(HealthDay News) – For schoolchildren, exposure to human papillomavirus (HPV)-causing warts in the family and school class is associated with an increased risk of wart development, according to a study published online April 22 in Pediatrics.

Sjoerd C. Bruggink, MD, from the Leiden University Medical Center in the Netherlands, and colleagues conducted a prospective cohort study to examine the correlation between HPV exposure and incidence of warts in a cohort of 1,134 children in grades one to seven in three Dutch primary schools. Hands and feet were inspected for the presence of warts at baseline and after 11–18 months of follow-up.

The researchers found that wart development had an incidence of 29 per 100 person-years at risk. The risk was increased for children with a white skin type (hazard ratio [HR], 2.3). Independent environmental risk factors included having family members with warts (HR, 2.08) and the prevalence of warts in class (HR, 1.2 per 10%  increase).

“This study reveals that the incidence of warts in primary schoolchildren is high and that cutaneous HPV is primarily transmitted via the family and school class,” the authors write. “Our findings suggest that recommendations should shift toward reducing transmission among families and school classes.”

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