Management and Prevention of Papillomaviruses Infection
Although they are a cosmetic nuisance in most cases, warts are notoriously difficult to treat. The treatments which could be used include cryotherapy with liquid nitrogen, podophyllin (an antimitotic agent), lasers (for mucosal lesions such as CIN), electrodiathermy, and surgery. Interferon has been used successfully to treat recurrent laryngeal warts and CIN. However, the cost of the treatment may prove to be prohibitive. Precancerous CIN-2 and CIN-3 lesions should be treated by lasers, electrodiathermy, or surgery. In the case of immunocompromised patients with intractable warts, improvement is often seen. There are mass screening programs for CIN and cervical cancers in a number of countries.
Being one of the most common cancers in women, a vaccine against HPV types associated with cervical cancers would be desirable and a lot of research has been carried out in this area. To date, there are two licensed vaccines available: Gardasil and Cervarix. They are made of VLP (virus-like particles) from the major capsid protein L1 of HPV strains. Cervarix contains L1 proteins of the cancer-associated strains HPV 16 and 18, which are associated with 70% of cervical cancers. Besides HPV 16 and 18, Gardasil contains HPV 6 and 11 which are associated with 90% of genital warts. The vaccines are designed to elicit the production of virus-neutralising antibodies and prevent the initial infection by those strains. The vaccines have been shown to offer 100 percent protection against the development of precancertous cervical cancer lesions and genital warts caused by the HPV types in the vaccine, with little or no side effects. The protective effects of the vaccine are expected to last a minimum of 4.5 years after the initial vaccination.
The target group for vaccination are women between 9 to 25 years of age who have not contracted HPV. Although HPV 6 and 11 do not cause cervical cancers, they cause genital warts that may result in considerable pain and discomfort. It is thought the inclusion of HPV 6 and 11 would make the vaccine more attractive, particularly to men who are not at risk of cervical carcinoma. Because of the high cost-benefit that may result from the prevention of cervical carcinoma, there are ongoing studies and proposals that aim make HPV vaccination available to schoolgirls in a a number of countries including the US, Canada, and Australia.