Incidence of Genital Warts in Sweden Before and After Quadrivalent Human Papillomavirus Vaccine Availability

• Published in: The Journal of infectious diseases Vol. 206; no. 6; pp. 860 - 866
• Main Authors: Leval, Amy, Herweijer, Eva, Arnheim-Dahlström, Lisen, Walum, Hasse, Frans, Emma, Sparén, Pär, Simard, Julia F.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 15-09-2012
• Subjects: Adolescent; Adult; Age Distribution; Age groups; Applied microbiology; Biological and medical sciences; Child; Condylomata acuminata; Condylomata Acuminata - epidemiology; Condylomata Acuminata - prevention & control; Epidemiology; Female; Fundamental and applied biological sciences. Psychology; Human papillomavirus; Human viral diseases; Humans; Incidence; Infections; Infectious diseases; Male; Medical sciences; Medicin och hälsovetenskap; Men; Microbiology; Miscellaneous; Papillomavirus Vaccines - administration & dosage; Papillomavirus Vaccines - immunology; Population estimates; Prescription drugs; Sweden - epidemiology; Time Factors; Vaccination; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Viral diseases; Viral diseases of the genital and urinary system; Virology; VIRUSES; Warts; Women; Young Adult; Scandinavia; Sweden; Europe; Papillomavirus; Virus; Infection; Human papillomavirus; Sexually transmitted disease; Viral disease; Condyloma acuminatum; Vaccine; Papovaviridae; Epidemiology; Incidence
• ISSN: 0022-1899; 1537-6613; 1537-6613
• DOI: 10.1093/infdis/jis405

Background. More than 90% of genital warts (GW) cases are caused by human papillomavirus (HPV) types 6 and 11. The introduction of HPV vaccines necessitates the estimation of the population-based incidence of GW immediately before and after vaccination uptake. Methods. Incidence proportions were calculated using the entire population aged 10-44 years living in Sweden during 2006-2010. The Prescribed Drug Register and the National Patient Register were used to define GW episodes. Time trends were estimated using Poisson regression. Results. In 2010, age-stratified incidence proportions of GW were highest for 20-year-old women (956 cases/100 000), while the incidence proportion among males was greatest at the slightly older age of 24 years (1137 cases/100 000). Crude rates were marginally higher among males than among females during 2006-2007 and appeared to later diverge. Between 2008 and 2010, the overall incidence appeared to increase among males, and the incidence among females declined. Females aged 17 and 18 years had a > 25% decline in GW rates between 2006 and 2010, with significant decreases through the age of 25 years. Conclusions. This study provides a reasonable estimation of the incidence of GW in the Swedish population by use of register data, with results comparable to those from previous smaller studies. There was a downward trend of GW incidence among younger females between 2006 and 2010.