The incidence of condyloma or genital warts (GW) is significantly declining in young women, according to a novel register study from Karolinska Institutet. The researchers suggest that this recent development may be explained by the introduction of the national HPV vaccine programme in Sweden.
Genital warts, referred to as anogenital warts or condyloma acuminate, are highly infectious and transmitted sexually primarily through skin-to-skin contact. Over 90 percent of GW are caused by Human papillomavirus (HPV) types 6 and 11. The introduction of HPV vaccines have made the estimation of population-based incidence of condyloma immediately prior to and following vaccination uptake necessary for the evaluation of vaccine programme effectiveness.
In the current study, which is published in the Journal of Infectious Diseases, incidence proportions were calculated using the entire population of men and women living in Sweden between 2006-2010 ages 10-44. To define episodes of GW the drug prescription and patient registers were used.
The results show that women ages 17 and 18 years had over a 25 percent decline in GW rates when comparing 2006 with 2010, with significant decreases through age 25. Incidence among men did not decline, indicating no possible herd immunity effects during this period.
Incidence of Genital Warts in Sweden pre and post Quadrivalent HPV Vaccine Availability. Amy Levál, Eva Herweijer, Lisen Arnheim Dahlström, Hasse Walum, Emma Frans, Pär Sparén och Julia Fridman Simard. Journal of Infectious Diseases, online 19 July 2012