The Quadrivalent Human Papillomavirus Vaccine in Recalcitrant Non-genital Warts: A Retrospective Study.

INTRODUCTION The human papillomavirus (HPV) vaccine has been reported to lead to clinical clearance of lesions when used as an off-label treatment for recalcitrant extragenital warts. The aim of the study is to evaluate the therapeutic and adverse effects of HPV vaccine as an adjunctive therapy for treatment-resistant acral warts. METHODS Patients with persistent warts despite first and second line therapies, and subsequently receiving the quadrivalent HPV vaccine between July 2013 and June 2016 as an adjunctive treatment for recalcitrant warts at the National Skin Centre, were included. RESULTS Twenty-six patients with a median age of 34 years (range 8 to 77 years) were treated with the HPV vaccine. Nineteen (73.1%) patients completed 3 doses of the vaccine, of whom 5 (26%) achieved complete clearance, 8 (42%) had partial clearance and 6 (32%) did not respond to the vaccine. Among the 4 patients who received 2 doses of the vaccine, 3 (75%) had complete clearance whereas 1 (25%) had partial improvement of their warts. None of the patients reported adverse reactions. CONCLUSION Our study suggests a potential adjunctive role of the HPV vaccine in the treatment of acral warts recalcitrant to conventional therapy.