HPV infection occurs when a type of HPV virus enter your body through a break in the skin or other body surface. Once inside, the virus infects skin cells called keratinocytes and reproduces itself. Active infection may or may not be associated with obvious symptoms. Signs of infection may not appear for weeks, months, or possibly even years after infection. The virus may remain active for up to two years or even longer, but in most cases it will become inactive and may persist in the body in a dormant state for long periods. During this time, the virus may be transmitted to another person. The longer that an infection remains active in the body, the greater is the risk that it may lead to cancer.

HPV is transmitted by skin-to-skin contact. HPV types that affect the genitals are transmitted by vaginal, anal, or oral sex or other skin-to-skin contact involving the genital region.

Certain types of HPV are called high-risk and are responsible for causing most cases of cervical cancer. Two types in particular, called type 16 and type 18, account for around 70% of all cases of cervical cancer.