14342 Clearance of recalcitrant warts in a pediatric patient following administration of the nine-valent human papillomavirus vaccine

Abstract

Verruca vulgaris (common warts) are a benign neoplasm of skin and mucous membranes caused by human papillomavirus (HPV) that are especially common in school-aged children. Spontaneous resolution of warts within two years is common, but recalcitrant cases can cause considerable morbidity in pediatric and adult patients. Although many therapeutic options for warts exist, there is no definitive cure. Several cases of recalcitrant common wart clearance following use of the bivalent, quadrivalent, or 9-valent HPV vaccine have been described. We report the case of a 10-year old girl with persistent cutaneous warts lasting three years which resolved completely following 2 doses of the 9-valent HPV vaccine. No recurrence of warts was noted 9 months after clearance. To our knowledge, this is the first report of recalcitrant common wart clearance in an immunocompetent pediatric patient with the 9-valent vaccine. The mode of action for this therapy is presently unclear, but comparative homology studies of the virus’s L1 capsid protein suggest the possibility of a cross protective effect. Interestingly, an age-dependent response to HPV vaccination has also been observed. Complete resolution is frequent in younger patients, while adult patients commonly experience incomplete clearance. Evidence shows that this effect may be partially due to hormonal changes during puberty. This case contributes to the growing body of evidence showing HPV vaccination to be a good alternative to other cutaneous wart treatments for pediatric patients and adds to our understanding of potential therapeutic use of the HPV vaccine.