Duration and clearance of anal human papillomavirus (HPV) infection among women: the Hawaii HPV cohort study

Clin Infect Dis. 2009 Mar 1;48(5):536-46. doi: 10.1086/596758.


Background: The association of anal cancer with human papillomavirus (HPV) infection is well established; however, little is known about the epidemiology of anal HPV in healthy women. We investigated patterns of duration and clearance of anal HPV infection in a cohort of healthy women in Hawaii.

Methods: Viral and nonviral determinants of anal HPV clearance were examined in a longitudinal cohort study of 431 sexually active women. At baseline and at 4-month intervals, interviews were conducted and cervical and anal cell specimens were obtained for detection of HPV DNA.

Results: Of the 431 women, 50% experienced a total of 414 incident anal HPV infections, reported at 1 clinic visits from baseline through a follow-up period of average duration of 1.2 years. Of these infections, 58% cleared during follow-up. The clearance rate for a high-risk anal infection was 9.2 per 100 woman-months (95% confidence interval [CI], 6.9-11.9 per 100 woman-months), with a median duration of 150 days (95% CI, 132-243 days). The slowest clearing high-risk HPV types were HPV-59 (median clearance time, 350 days) and HPV-58 (median clearance time, 252 days). The median clearance times for HPV-16 and HPV-18, the predominant types associated with anal cancer, were 132 days and 212 days, respectively. Nonviral factors that delayed clearance of anal HPV included douching, long-term tobacco smoking, and anal sex.

Conclusions: The majority of anal HPV infections resolve in a relatively short time. Although anal HPV is commonly acquired in healthy women, its rapid clearance suggests limited efficacy of HPV testing as an anal cancer screening tool.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Anal Canal / pathology
  • Anal Canal / virology*
  • Cervix Uteri / virology
  • Cohort Studies
  • Female
  • Hawaii / epidemiology
  • Humans
  • Longitudinal Studies
  • Middle Aged
  • Papillomaviridae / classification
  • Papillomaviridae / genetics
  • Papillomaviridae / isolation & purification
  • Papillomavirus Infections / drug therapy
  • Papillomavirus Infections / epidemiology*
  • Papillomavirus Infections / virology*
  • Proctitis / drug therapy
  • Proctitis / epidemiology*
  • Proctitis / virology*
  • Time Factors