Wednesday, 14 October 2009

Human Papillomavirus (HPV) And The Vaccine.


A human papillomavirus is a papilloma virus that infects the epidermis (skin) and mucous membranes of humans. HPV can lead to cancer of the cervix, vulva, vagina and anus in women. I men, it can lead to cancers of the anus and penis.

Approximately 130 HPV types have been identified. Some HPV types can cause warts (verrucae), but those types don't cause cancer. Other types can cause cancer, but those types don't cause warts. Other types have no symptoms and are harmless. Most people who become infected with HPV do not know they have it.

About 30-40 HPV types are typically transmitted through sexual contact and infect the anogenital region. Some types may cause genital warts. Persistent infection with "high-risk" HPV types—different from the ones that cause warts—may progress to pre-cancerous lesions and invasive cancer. HPV infection is thought to be the cause of most cases of cervical cancer. However, most HPV infections in young females are temporary and have little long-term significance. 70% of infections are gone in 1 year and 90% in 2 years.

Most people have now heard of the HPV vaccines which are now being offered to young teenage females. Two vaccines are available, which are designed to prevent infection by some HPV types, Gardasil, marketed by Merck and Cervarix, marketed by GlaxoSmithKline. Both are intended to protect against initial infection with HPV types 16 and 18, which cause most of the HPV associated cancer cases. Gardasil is also said to protect against HPV types 6 and 11, which cause 90 percent of genital warts.

Both vaccines are delivered in three shots over six months. In most countries they're approved only for female use.

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