December 20, 2010

HPV...Human papillomavirus

Vaccinating 13 year old girls with human papillomavirus vaccine (HPV) can help reduce cases of cervical cancer and genital warts. Studies had shown that teenage girls aged less than 15 have a better immunity response compared with older girls or women.

Immunity among teenagers (15 years and below) vaccinated with HPV is very high even after five and a half years. Free HPV vaccination programme carried out by the government for teenage students was an initiative to prevent cervical cancer. HPV is a common virus that is passed on through genital contact, most often during sex and most sexually active people will get HPV at some time in their lives, though most will never even know it and is most common among people in their late teens and early 20s.  Malaysian women were at a high risk of HPV which can led to cervical cancer due to their smoking habits, diet and family history.

According to the World Health Organisation (WHO) 80 percent of women who have reached 50 years would have been affected by HPV and almost 20 percent of them would have reached a chronic stage, resulting in cervical cancer. The government would be spending RM150 million to vaccinate about 300,000 teenagers throughout the country.

A human papillomavirus (HPV) is a member of the papillomavirus family of viruses that is capable of infecting humans. Like all papillomaviruses, HPVs establish productive infections only in the stratified epithelium of the skin or mucous membranes. While the majority of the nearly 200 known types of HPV cause no symptoms in most people, some types can cause warts (verrucae), while others can – in a minority of cases – lead to cancers of the cervix, vulva, vagina, and anus in women or cancers of the anus and penis in men.

More than 30 to 40 types of HPV are typically transmitted through sexual contact and infect the anogenital region. Some sexually transmitted HPV types may cause genital warts. Persistent infection with "high-risk" HPV types—different from the ones that cause skin warts—may progress to precancerous lesions and invasive cancer. HPV infection is a cause of nearly all cases of cervical cancer; however, most infections with these types do not cause disease.

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. However, when the infection persists—in 5% to 10% of infected women—there is high risk of developing precancerous lesions of the cervix, which can progress to invasive cervical cancer. This process usually takes 15–20 years, providing many opportunities for detection and treatment of the pre-cancerous lesion. Progression to invasive cancer can be almost always prevented when standard prevention strategies are applied - however the lesions still cause considerable burden necessitating preventive surgeries which do in many cases involve loss of fertility.

In more developed countries, a cervical Papanicolaou (Pap) test is used to detect abnormal cells which may develop into cancer. During a colposcopic inspection biopsies can be taken and abnormal areas can be removed with a simple procedure, typically with a cauterizing loop or—more common in the developing world—by freezing (cryotherapy).

Pap smears have reduced the incidence and fatalities of cervical cancer in the developed world, but even so there were 11,000 cases and 3,900 deaths in the U.S. in 2008. Cervical cancer has substantial mortality in resource-poor areas; worldwide, there are 490,000 cases and 270,000 deaths.

HPV vaccines (Cervarix and Gardasil), which prevent infection with the HPV types (16 and 18) that cause 70% of cervical cancer, may lead to further decreases.