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'. 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.
Public Health England (PHE) has developed laboratory, modelling and surveillance techniques and systems to describe and monitor the type-specific epidemiology of HPV infections and related disease, and to investigate the impact of HPV immunisation.
Cervical cancer is the second most common cancer in females worldwide and is the 11th most common cancer in females in the UK. HPV is a necessary, although not sufficient, cause of cervical cancer. Over 70% of cervical cancers are attributed to two types: HPV 16 and 18. High risk HPV infections are also associated with cancer of the penis, vulva, vagina, anus, mouth and oro-pharynx.
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. The HPA routinely collects data on STIs from genitourinary medicine (GUM) clinics (STI Annual Data Tables).
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; one vaccine also protects against HPV types 6 and 11. Both vaccines are prophylactic, meaning they should be given prior to HPV infection.
In the UK, all 12-13 year old girls (school year 8) are offered HPV vaccination through the national HPV immunisation programme. Girls aged up to 18 years are eligible for immunisation as part of the catch-up campaign. From September 2008 until August 2012 the programme used the bivalent HPV vaccine (CervarixTM, GlaxoSmithKline) that protects girls against infection with HPV 16 and 18 (associated with over 70% of cervical cancers in the UK). From September 2012, 12-13 year old girls are offered the quadrivalent vaccine (Gardasil, Sanofi Pasteur MSD) which protects against types 16 and 18 and also against types 6 and 11 (associated with the majority of genital warts). Annual uptake data are provided by the Department of Health.
Although there is no known risk associated with giving HPV vaccines during pregnancy or whilst breast-feeding the HPV vaccine is not advised in pregnancy as a precaution. PHE is following women who are inadvertently vaccinated while pregnant to gain information that will 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 PHE Immunisation Department.