Decline in hospitalization for genital warts in the Veneto region after an HPV vaccination program: an observational study

BACKGROUND Human papillomavirus (HPV) is one of the most common sexually transmitted pathogens. This observational study was conducted to estimate the trend of hospitalization for genital warts (GWs) in the Veneto region (Italy) from 2004 to 2015. METHODS All patients with GWs were identified in the hospital discharge records of all public and accredited private hospitals that related to Veneto residents and contained the ICD9-CM code 078.11 associated with a genital surgical procedure (vulval/vaginal warts, penile warts and anal warts). Annual total and sex- and age-specific hospitalization rates and trends were calculated and correlated with the different HPV vaccine coverage over the study period. RESULTS An annual rate of 11.8 per 100,000 population (8.6 per 100,000 males, and 14.8 per 100,000 females) was found, corresponding to 6076 hospitalizations for condyloma (53.3% vulval/vaginal, 35.8% anal, 8.3% penile, and 2.6% both penile or vulval/vaginal and anal). Among females, the rate of overall GWs remained stable to 2007 (19.1 per 100,000), then dropped significantly, reaching a rate of 11.3 per 100,000 in 2015 (average annual percent changes [AAPC]: -6.1%; 95% CI: -8.4; -3.7). For males, the overall rate increased over the study period (from 6.4 per 100,000 in 2004 to 10.8 per 100,000 in 2015; AAPC: 3.8%; 95% CI: 1.2; 6.4). Among the potentially vaccinated females (12- to 20-year-olds) there was a 62.1% decrease in the number of vulval/vaginal warts from the years 2010-2012 to the years 2013-2015 due to an increase in the HPV coverage rate. A similar reduction among males was observed in the same period and the same age group for penile warts (-68.2%). CONCLUSION GWs have an important impact on the health services and data suggest that GW-related hospitalization rates rapidly decline in a population with a high HPV vaccination coverage (about 75%). Further efforts should be made to better clarify the epidemiological picture regarding HPV-related diseases, with particular regard to sexual behavior.