According to a cohort study, HPV cumulative incidence rates are associated with younger women, certain ethnic groups and high frequency of alcohol consumption. Forty-three percent of women, who had attended at least one follow-up visit, were HPV negative. The incidence tended to decrease by 20% in the first year, 14% and 9% in the second and third years, respectively. The median duration of HPV infection was 8 months. 70% of women were no longer infected one year after the incident and 9% continued to be infected for two years. The longest median duration of infection was established for HPV 16, 18, 61, 73 and AE7. In developed countries, the highest rates of HPV infection have been observed among 15-25-year old women who might reflect transmission during their first sexual intercourse whereas the infection rate Jira Chansaenroj et al