Two doses of the vaccine Cervarix targeting human papilloma virus (HPV) were discovered to be as effective as the current standard three-dose regimen after four years of follow-up, according to researchers from the National Cancer Institute (NCI), part of the National Institutes of Health, and their colleagues. The results of the study, based on data from a community-based clinical trial of Cervarix in Costa Rica, appeared online Sept.9, 2011, in the Journal of the National Cancer Institute.
Worldwide, approximately 500,000 new cases of cervical cancer are diagnosed every year, and about 250,000 women die from the disease. An overwhelming majority of these new cases and deaths occur in low-resource countries. Virtually all cases of cervical cancer are caused by persistent infection with HPV. Cervarix is one of two vaccines approved by the U.S. Food and Drug Administration for the prevention of cervical cancer caused by HPV types 16 and 18, which together account for 70 percent of all cervical cancer cases. The vaccine is intended to be administered in three doses given over the course of six months. To date, investigators have observed up to eight years of protection from persistent HPV infection with the vaccine. Studies are ongoing to determine the maximum length of protection.
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