Human papillomavirus infection in Danish female sex workers. Decreasing prevalence with age despite continuously high sexual activity.

BACKGROUND: The prevalence of the human papillomavirus (HPV) has been found to decrease with age, but whether this applies to all populations is not clear. Knowledge about the generalizability of this age dependency is important to understand the natural history of the infection, but may also have implications in relation to the use of HPV testing in cervical cancer screening.

GOAL: To study the prevalence and risk factors for HPV infection in a selected population of female sex workers and to compare the results with persons with different sexual habits from two other populations in the same geographic area.

STUDY DESIGN: A case-control study among 188 female sex workers from Copenhagen. Data were obtained by personal interviews. Cervical material was collected by a self-administered lavage kit, and HPV testing was done by means of GP5+/6+ primers based on HPV, polymerase chain reaction, enzyme immunoassay.

RESULTS: Among sex workers, age was the most important risk factor for HPV infection. Number of private sex partners in the last 4 months was also a significant risk factor, and a protective effect of condom use was indicated.

CONCLUSION: The HPV prevalence is declining in sex workers with age despite continuously high sexual activity, most likely indicating that an immune response is acquired over time.