Two Doses of HPV Vaccine May Work as Well as
THURSDAY, Sept. 8 (HealthDay News) -- Two doses of the human
papillomavirus (HPV) vaccine may offer just as much protection
against cervical cancer as the three-dose regimen now being used,
new U.S. government research shows.
The findings stem from an analysis of data from the National
Cancer Institute's Costa Rica Vaccine Trial, in which 7,466 women
were enrolled, according to a news release from the
Journal of the National Cancer Institute, which published the
results on Thursday.
The women were either given the HPV vaccine Cervarix or a
Hepatitis A vaccine. Although researchers intended to give the
women receiving Cervarix the full three doses, 20 percent of them
got only one dose or two doses for a variety of reasons.
After four years, the researchers found, two doses of Cervarix
offered the same level of protection against HPV infection as
three. Even one dose offered a high level of protection.
While the researchers said that more studies are needed to
evaluate the long-term effectiveness of the fewer doses, they wrote
in a journal news release: "Our clinical efficacy data provide
suggestive evidence that an HPV vaccine program that provides fewer
doses to more women could potentially reduce cervical cancer
incidence more than a standard three-dose program that uses the
same total number of doses but in fewer women."
Cervarix is one of two vaccines approved by the U.S. Food and
Drug Administration to protect against the two types of HPV, 16 and
18, that are responsible for 70 percent of cervical cancer cases
around the world every year.
The analysis was led by Aimee R. Kreimer, of the division of
cancer epidemiology and genetics at the U.S. National Cancer
In an editorial accompanying the journal article, Cosette Marie
Wheeler, of the University of New Mexico, noted, "The age-old adage
of less is more may apply to HPV vaccination, and if so, the report
... represents an important step on the road to more effective and
sustainable cervical cancer prevention programs."
The U.S. Centers for Disease Control and Prevention provides
more information on
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