Human papillomavirus (HPV) - cervical cancer and genital warts
There are more than 100 types of HPV (human papillomavirus), including 40 which can infect the genital tract and are sexually acquired. Genital HPV infections are frequently asymptomatic and resolve without causing disease. However, certain HPV infections can cause cervical cancer, other cancers and genital warts.
HPV types associated with cancer are called oncogenic or 'high risk' types; 13 have been recognised by the WHO International Agency for Research on Cancer. HPV types that do not cause cancer are termed 'low risk' types. Two of these 'low risk' types cause genital warts. HPV types are referred to by number (assigned in the order in which they were discovered).
HPV infections are extremely common in the sexually active population and are particularly common in the first few years after onset of sexual activity.
Cervical and other cancers
Cervical cancer is the second most common cancer in females worldwide and is the 12th most common cancer in females in the UK. HPV is a necessary, although not sufficient, cause of cervical cancer. Around 70% of cervical cancers are attributed to two types: HPV 16 and 18. At least 10 other HPV types are also associated with a high risk of cervical cancer (e.g. HPV 31, 45). High risk HPV infections are also associated with cancer of the penis, vulva, vagina, anus, mouth and oro-pharynx.
Genital warts
Warts are the most common viral STI diagnosed in the UK, with highest rates of new cases in 20-24 year old men and 16-19 year old women. Warts are found on or around the penis, anus or vagina. Low risk HPV types 6 and 11 cause the majority of genital warts. The number of genital warts diagnosed in the UK population has continuously risen since records began in 1971.
Health Protection Report: Trends in genital warts and herpes diagnoses in the United Kingdom (PDF, 375 KB)
Prevention
Cervical screening can detect pre-cancerous lesions and cervical cancers at early asymptomatic stages, when they can be successfully treated.
Two HPV vaccines have been developed that can protect against HPV type 16 and 18 infection (associated with 70% of cervical cancer); one of these also protects against HPV types 6 and 11 (genital warts). Both vaccines are prophylactic, meaning they should be given prior to HPV infection.
UK HPV immunisation programme
In the UK, a national HPV immunisation programme will be introduced for all girls aged 12-13 years (school year 8) starting in Autumn 2008. The national immunisation programme will use the bivalent HPV vaccine (CervarixTM, GlaxoSmithKline) and will protect girls against infection with HPV 16 and 18 (associated with 70% of cervical cancers). There will be a catch-up campaign for girls aged up to 18 years (women born on or after the 1st September 1990). In England the catch up campaign will be conducted over 3 years starting in Autumn 2008 targeting 17-18 year olds. The Joint Committee on Vaccination and Immunisation (JCVI) has advised that the programme would be most efficiently delivered through schools. Primary Care Trusts in England will plan local delivery of the HPV vaccination programme. The JCVI advised that a catch-up programme for all women aged 18-25 years was unlikely to be cost effective but could benefit some individual women: the Department of Health is considering this further.
HPV Vaccine given in pregnancy
There is no known risk associated with giving HPV vaccines during pregnancy or whilst breast-feeding. However, as a matter of caution, HPV vaccine is not advised in pregnancy. The HPA is following all women who are inadvertently given the HPV vaccine while pregnant to gain information that will help better inform pregnant women, their families and health professionals in the future. This surveillance is part of the UK Vaccination in Pregnancy Surveillance Programme being run by the HPA Immunisation Department.