Human papilloma virus

HPV is a double-stranded DNA virus that infects the surface of the skin and mucosae of the upper respiratory and anogenital tracts

• are over 100 types of HPV viruses of which about 40 infect the genital tract
  
  
  • classified as being either high risk or low risk depending upon their association with the development of cancer
    
    
    • Types 16 and 18 are high risk and types 6 and 11 are low risk
      
      
    • Types 16 and 18 account for around 80% of all cervical cancers, the remaining 20% are due to 11 other high-risk HPV types
      • the proportion of cancers of the anus, penis, mouth and throat, vagina and vulva which are related to a high-risk HPV infection (and which are caused by types 16 and 18) vary by cancer site
        
        
    • majority of HPV infections do not cause any symptoms and infection is usually cleared by the body's own immune system without the need for other treatment
      • 70% of new high risk infections will clear within a year
      • 90% of new infections clear within 2 years
        
        
    • persistent infection with high risk HPV types such as types 16 and 18 can cause cell changes leading to lesions, warts or ano-genital cancers. These include cancer of the cervix, vulva or vagina in women, cancer of the penis in men and some cancers of the head, neck, throat or anus in either sex. Other types of HPV such as 6 and 11 cause genital warts which is the most commonly-diagnosed viral sexually-transmitted infection in the UK
      • HPV types 6 and 11 are associated with a more benign form of genital warts
      • HPV types 16 and 18 are associated with an aggressive form of genital warts
        
        
• Transmission of HPV
  • HPV infections are spread primarily by sexual contact with an infected partner, particularly through sexual intercourse but also by non-penetrative genital contact, including oral sex
  • HPV is one of the most commonly transmitted sexually-transmitted infections in the UK and anyone who is sexually active can contract it. The risk of acquiring infection increases with the number of previous sexual partners, the introduction of a new sexual partner, and the sexual history of partners
  • Infection commonly occurs soon after sexual debut and almost 40% of women are infected within two years (5)

Reference:

• DOH (UK). The 'Green Book' chapter on Human papillomavirus (HPV) - accessed 24/7/19
• Public Health England (PHE). Vaccine update: issue 296, July 2019, HPV special edition