The HPV virus is mainly infected through sexual intercourse, there is no need to worry too much about sexual intercourse will definitely be infected, there is a history of smut or multiple sexual partners can increase the chance of HPV virus infection. HPV infection is mainly through sexual intercourse, but other modes of infection still exist. The HPV vaccine is best administered in the teenage years, when the probability of HPV infection is low and immunity to antigens is good because sexual activity has not yet begun.