This is a magnified picture of the virus:
The virus sits on the surface of the skin in these areas and can be passed on by close intimate skin to skin contact or by having sex (vaginal, oral or anal) with an infected person.
Condom use is not as effective in preventing HPV as other sexually transmitted infections such as chlamydia and HIV. This is because the condom does not cover a large enough area of the body.
Most people infected with HPV do not have any symptoms at all.
Some people develop genital warts.
Any young person who has had sex with another person may be at risk.
If someone is concerned they might have genital warts, they should speak to their GP (family doctor) or attend a local (genitourinary) sexual health clinic .
This STI is a serious health concern as 70% of cancers of the cervix have been linked to HPV. Because of this, a new immunisation programme has started, to vaccinate girls between the ages of 12 and 17.
It is given in a course of three injections over six months and is currently being offered in schools to all Year 8 girls.
The vaccine is most effective when administered to girls before they become sexually active, so before they potentially come into contact with HPV. However, the vaccine only targets the two strains of HPV that cause cervical cancer and is not effective against the strains that cause the warts.
For help or advice see the section called TALK on the Students page.