TRANSMISSION OF ANOGENITAL HPV INFECTION
| KEY POINTS |
|---|
| HPV is spread from close skin-to-skin contact. |
| Transmission in the genital region may occur even when condoms are used and does not necessarily require penetrative intercourse. |
| If one member of a stable partnership has anogenital HPV infection, the other is likely to be either infected or immune to that infection. |
| Condoms provide limited protection against HPV infection, but their use is recommended to prevent other sexually transmitted infections. |
| Because of variable latency, HPV infection may develop during a long-term relationship and does not necessarily imply other sexual contacts. |
Sexual transmission
HPV infection results from skin-to-skin contact and can be transmitted by penetrative as well as non-penetrative sexual contact (27) (genital-genital, oral-genital, anal-genital, oral-anal). Other types of contact may also play a role; such as spread during sexual activity through fingers or sex toys from genital areas infected with HPV.(28) Anal intercourse is not required for spread to the anal canal. The prevalence of HPV infection is much lower in virgins (4% vs 22% in sexually active women in a report from Sweden).(29) The virus is not transmitted via blood or body fluid, e.g. semen. Transmission occurs frequently because subclinical infections are common and asymptomatic, and warty lesions often go unnoticed, particularly in areas that are not easily inspected for the presence of warts. Among heterosexual couples, type specific concordance (both partners infected with the same HPV type) is common,(30) almost 25%.
It is generally believed, although not proven, that clinically visible warts offer the greatest possibility for transmission, and that treating warts decreases that possibility.
Anogenital HPV infection can be transmitted to the mouth through oral sex.(31) The mouth appears to be a less hospitable environment for genital strains of HPV than the genital area.(32-35)
Immunity from natural infection is generally poor. Naturally produced antibodies provide partial protection, although many people do not seroconvert.(36,37) Previous infection does not necessarily create long-term immune memory so does not prevent future re-infection with the same HPV type.
Non-sexual transmission
Vertical transmission in utero is very rare (38) (see Pregnancy and Breastfeeding). Autoinoculation may occur rarely.(39) While HPV DNA has been found on fomites (inanimate objects), there is no evidence to suggest that transmission occurs.(40,41)
For management of HPV infection in children, see Guidelines on the Management of Anogenital HPV in Childhood.
Condom use
Consistent condom use has been shown to reduce the risk of acquisition of HPV infection and genital warts (in the order of 30-60% reduction).(42-44) They may reduce recurrence when both partners are infected,(45-47) although the extent to which recurrence is due to re-infection is not known.
Vaccine
HPV vaccine is a very effective method of preventing HPV acquisition – see HPV Vaccines.
The Ministry of Health supports the use of these clinical guidelines, developed by clinical experts and professional associations to guide clinical care.
Produced by the Professional Advisory Board (PAG) of the Sexually Transmitted Infections Education Foundation
Website by Original Image