NEW YORK (Reuters Health) — Young women commonly become infected with the human papillomavirus (HPV) soon after they start having sex, but the infection usually clears quickly, a new study shows.HPV is a sexually transmitted infection that causes genital warts, and persistent infection with certain strains of the virus can lead to cervical cancer.

In the current study, researchers followed 206 Costa Rican women ages 18 to 26 who initially said they were virgins. After becoming sexual active, they were followed for an average of 3.6 years. During this time, 53 percent tested positive for HPV, the study found.

However, few of these infections persisted for more than one to three years, and only three women developed pre-cancerous changes in their cervical cells.

“HPV infection occurs frequently and clears rapidly in most young women initiating sexual intercourse,” the study authors write in the journal Sexually Transmitted Diseases.

Still, in a small number of cases, persistent infection with cancer-related HPV strains may cause pre-cancerous cervical changes within just a few years, according to the researchers, led by Dr. Ana Cecilia Rodriguez of the US National Cancer Institute.

Of the three young women who developed such abnormalities in this study, two were related to the HPV-16 strain, which is one of the strains targeted by the Gardasil HPV vaccine. In the US, health officials recommend routine HPV vaccination for girls ages 11 to 12, as well as girls and women between the ages of 13 and 26 who haven’t yet been vaccinated.