Human Papillomavirus (HPV): Facts and Vaccines

Facts:

• HPV vaccines are close to 100% effective in preventing HPV infection and precancerous conditions that may lead to cervical cancer, if the vaccine is given before a person is exposed to the HPV types contained in the vaccine.
• HPV vaccines appear to be safe and generally are well tolerated.
• Two HPV vaccines have been developed. Both prevent infection with type 16 and -18, and may prevent up to 70% of cervical cancers. One of the vaccines also prevents infection with HPV-6 and -11, and may prevent about 95% of genital warts.

Human papillomavirus (HPV) causes cervical cancer which is the second most common cancer in women worldwide by age-standardized incidence rate (ASR). In 2008, there were an estimated 529,000 new cases and 274,00 deaths due to cervical cancer. More than 85 % of cervical cancer deaths are in developing countries, where it accounts for 13% of all female cancers.

Human papillomaviruses are common throughout the world. Although most infections with HPV cause no symptoms, persistent genital HPV infection can cause cervical cancer in women. Virtually all cervical cancer cases (99%) are linked to genital infection with HPV which is the most common viral infection of the reproductive tract. HPV can also cause other types of anogenital cancer, head and neck cancers, and genital warts in both men and women. HPV infections are transmitted through sexual contact.

Two HPV vaccines are now being marketed in many countries throughout the world. Both vaccines are highly efficacious in preventing infection with virus types 16 and 18, which are together responsible for approximately 70% of cervical cancer cases globally. They are also highly efficacious in preventing precancerous cervical lesions caused by these types. One vaccine is also highly efficacious in preventing anogenital warts, a common genital disease which is virtually always caused by infection with HPV types 6 and 11. The primary target group in most of the countries recommending HPV vaccination is young adolescent girls. Data from clinical trials and initial post-marketing surveillance conducted in several continents show both vaccines to be safe.