== Warnings ==
* Although most HPV infections clear up on their own and most pre-cancerous lesions resolve spontaneously, there is a risk that HPV infection may become chronic and pre-cancerous lesions progress to invasive cervical cancer. It takes 15 to 20 years for cervical cancer to develop in people women with normal immune systems. It can take only 5 to 10 years in people women with weakened immune systems, such as those with untreated HIV infection.
* Anal cancer affects both males and females and although relatively rare, in 2005 there were 149 cases in males and 176 cases in females. Infection with certain types of "high-risk" HPV types (such as HPV types 16 and 18) is a risk factor for anal cancers as well as other risk factors including cigarette smoking, immunodeficiency syndromes and a previous history of genital cancers.