HPV infection of the male and female anogenital tract is the most common sexually transmitted disease in the United States. Infection with HPV is strongly associated with both cervical dysplasia and cervical cancer. In fact, 99.7% of cervical neoplasia is attributable to HPV infection.
15 HPV can infect almost all human skin and epithelial surfaces with potential oncogenicity in those sites, both in males and females. Viral transmission requires intimate contact between partners but does not depend on sexual penetration or intercourse for its transmission. Most HPV infections occur in young women and are transient. In a study in the United States, the prevalence of HPV among women aged 14 to 59 years was about 27%.
16 The same study found that approximately 25% of girls ages 14 to 19 years had detectable HPV infection at the time of the analysis. The percentage of detectable HPV infection for other age groups were as follows: 34% of women ages 20 to 24 years, 27% of women ages 25 to 29 years, 28% of women ages 30 to 39 years, 25% of women ages 40 to 49 years, and 20% of women ages 50 to 59 years.
16 In sexually active women, the point prevalence of HPV infection declines after 30 years of age, but there is an
increase in point prevalence after age 50 years that may be related to changes in immune and hormonal status that occur following menopause.
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17,
18 Important to also note is a change in lifestyle or sexual partners in women of any age, which may lead to new HPV infection.
Although HPV infection is a necessary element for the development of cervical neoplasia, it is transient in 90% of women and becomes undetectable in 2 years.
19 Risk factors for acquiring HPV include sexual behavior, increasing frequency of sexual intercourse, early age of first coitus, number of lifetime sex partners, the male partner’s number of lifetime sex partners, age, ethnicity, HIV infection, and smoking or living with smokers.
12,17,20 Smoking is thought to potentiate the oncogenic potential of the HPV. Various carcinogens concentrate in cervical mucus and thus further contribute to oncogenesis.
21 Factors such as oral contraceptive use, increased gravidity, and immunosuppression have been reported but are less clearly associated. Most infections with HPV are transient or intermittent, with a median duration of 8 months.
17,18,22 Although adolescent women are at increased risk for infection due to the immature transitional zone (ectropion) of the cervix, both young and adolescent women are more likely to clear the infection. HPV infections and early cervical dysplasia represents a transient infection with up to 60 and 91% regression at 12 and 36 months, respectively, in women younger than 21 years of age.
23 Considerable geographic variation in the distribution of HPV genotype has been reported. Women in Europe appear to be more likely infected with HPV-16 than women in sub-Saharan Africa. Also, in Europe and the United States, the most common oncogenic HPV genotypes remain 16 and 18.
11,16,24
It is clinically important to know that prior infection with any one or multiple types of HPV has not been shown to confer immunity or protection from acquisition of another type of HPV.
25 This is also true with the vaccines, which are widely underused and which will be discussed further.