Identification of people at high risk of genital HPV infections.
Clinical and subclinical genital HPV infection is most prevalent in people aged 20-24 years. HPV-infected women have an earlier debut of sex activity, more partners and more casual relationships and STD than age-matched controls without HPV; although data are not available, the same risk factors probably operate in men. There is no evidence that the presence of non-genital warts affects the incidence of genital lesions. Between 50 and 70% of sex partners of individuals with condylomatous or non-condylomatous genital HPV infection also have lesions. Nothing is yet known about any relationship between infectivity and the number of lesions or their viral content. The infectivity of non-condylomatous HPV infection is uncertain. Immunological factors affect the clinical behaviour of genital warts, and immunosuppression, for example by drugs, radiation and possibly cigarette smoking and the use of oral contraceptives, may increase liability to genital HPV infection. The main risk factors appear to be young age, sexual promiscuity, intercourse with a partner with HPV disease and perhaps deficient immune responses. The identification of people at high risk requires careful clinical examination supplemented by the use of a magnification system, histology and cervical cytology. The identification of HPV genotypes in genital epithelia does not seem to be useful in this context, because they are present in a proportion of normal epithelia.