HPV - Human Papilloma Virus
The Human Papilloma Virus (HPV) is a virus belonging to the group of papillomaviruses. HPV infections are extremely common in the population and the route of transmission is through direct, generally sexual, contact with an infected person.
The use of a condom does not completely eliminate the risk of infection since the virus often infects even the skin that remains unprotected by the condom. In most cases the infection is asymptomatic and the virus is eliminated by the immune system before a pathogenic effect develops. However, HPV infection can result in a persistent viral disease that manifests with a variety of skin and mucosal lesions. More than 100 types of HPV have been identified; most of these cause lesions like common warts, often found in the hands and feet. About 40 types of HPV instead infect the mucous membranes, especially genital, causing venereal warts, also known as condylomata acuminata or ‘rooster crests’. Some lesions may evolve into severe neoplastic forms. For this reason, the types of HPV (serotypes) that infect the mucous membranes are divided into two types:
- low risk (non-oncogenes): these cause benign genital lesions with a low risk of malignant transformation (the most common are serotype 6 and 11, which alone are responsible for about 90% of venereal warts).
- high risk (oncogenes): these cause genital lesions with a high risk of malignant transformation. (The most common are serotype 16 and 18, which together account for about 70% of cervical cancers, as well as other cancers of the anogenital region).
The most common cancer linked to HPV is cervical cancer. However, following infection with oncogenic types of HPV, other forms of malignant neoplasm can also occur in the genitals (vulva, vagina, penis), in the anorectal area and in the oropharynx. In addition, some types of HPV can also infect the respiratory tract causing, for example, laryngeal papillomatosis.
Impact on the population
Without a doubt, the most-feared effect of HPV infection is cervical cancer, due to its severity and frequency. It is in fact the second most frequent cancer in women, with around 500,000 new cases per year and 250,000 deaths worldwide, and is the first cancer to be recognised by the WHO (World Health Organization) as totally attributable to an infection. In Italy, about 3,500 new cases of cervical cancer and 1,500 deaths occur every year. It is estimated that at least 75% of sexually active women become infected during their lives with a HPV virus of some kind, and that over 50% are infected with a high-risk oncogenic type. The majority of women with HPV infection fortunately will not develop cancer, however the infection is a prerequisite for its development.
Prevention can be implemented through screening, using a pap-smear or HPV-DNA, (recommended every three years for women aged between 25 and 64), allowing early identification and treatment of the cellular atypia that precede cervical cancer, as well as through vaccination.
Sources / Bibliography
- Epidemiology and Prevention of Vaccine-Preventable Diseases, The Pink Book: Course Textbook, 12th Edition Second Printing (May 2012)