For HPV vaccine, one dose goes a long way
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For HPV vaccine, one dose goes a long way

The recommended dose for human papillomavirus (HPV) vaccine Cervarix may be overkill in some settings, according to a new analysis. The vaccine, which prevents certain types of cervical cancer, has seen poor adoption, particularly in developing countries. There, the prescribed series of three injections is a financial and logistical burden for those without easy access to health care. But a reanalysis of two efficacy trials, sponsored by the National Cancer Institute and Cervarix’s maker, GlaxoSmithKline, suggests that even one dose confers roughly the same protection against the virus after 4 years as two or three doses do. Women in the trials who missed both follow-up doses of Cervarix still saw a rate of protection of 85.7% against HPV types 16 and 18, the strains that account for 70% of cervical cancers and for which Cervarix was designed. But three doses were more effective than one or two at preventing several less common carcinogenic HPV types—31, 33, and 45. Two doses spaced at least 6 months apart appeared to have the same effect as three. In a comment that ran today with the paper in The Lancet, Julia Brotherton of Australia’s National HPV Vaccination Program Register in Melbourne—who was not involved in the work—says the finding “opens up a great opportunity to extend the reach of protection … to more people than we would have previously thought possible.”