Human papillomaviruses

Papilloma Virus Humain (National Institutes of Health, USA)

Human papillomaviruses (HPV) are viruses that infect skin or mucosal epithelial cells, affecting men and women. Some varieties can affect the cervix, anal and oropharyngeal mucosa, and cause cancer of these areas of the body.

How are viruses transmitted?

Some varieties are transmitted by skin contact or indirectly (linen, toilets, swimming pools…), causing a skin infection (warts). Others are sexually transmitted (skin to skin contact, skin to mucous membranes), and develop condylomas (vulva, vagina, penis, scrotum…), also called genital warts (HPV6 and HPV11 varieties mainly, very little carcinogenic), or cancers (HPV16 and HPV18 varieties mainly).

Papillomavirus and cervical cancer

HPV16 and HPV18 together account for nearly 70% of cervical cancers worldwide. Other factors that may contribute to these cancers include smoking or HIV infection. However, not all infections, usually mild, lead to the development of cancer. Common especially among sexually active young women, they most often regress spontaneously. In less than 10% of cases, however, the infection persists. Some develop into precancerous lesions and reported cancer. About ten years can elapse between infection and the onset of cancer. According to the French National Cancer Institute, the mortality rate in France is 1.8 per 100,000 women.

Prevention and screening

Prevention against sexually transmitted papillomaviruses involves preventing sexually transmitted infections (condom use, partner testing). The screening is carried out every three years by the cervico-uterine smear at a gynaecologist, but also at a general practitioner or a midwife. This makes it possible to diagnose and treat pre-invasive lesions or cancers at an early stage, given the very long time between contamination and the possible appearance of precancerous lesions.

There are also two controversial HPV16 and HPV18 vaccines in France. They do not exempt regular smears from the age of 25 (or 8 years after the first sexual intercourse), a very effective means of prevention that has made it possible, since the 1960s, to reduce both the incidence and mortality of cervical cancer. In France, it is the 11th most common cancer among women, far behind breast, colon-rectal and lung cancers. In the USA, HPV is the most common sexually transmitted infection.

Treatment

Most contaminations resolve themselves. Precancerous lesions are treated surgically, while reported cancers are treated with surgery, radiotherapy and chemotherapy.