NEW YORK — Two doses of Merck & Co.’s human papillomavirus vaccine might be just as effective in younger girls as the recommended three doses given to older teens and women to help protect them against the virus that causes cervical cancer, a Canadian study found.
Girls ages 9 to 13 who received two doses of Gardasil had antibody levels that were not worse than females ages 16 to 26 who received three doses, according to research published yesterday in the Journal of the American Medical Association.
The study is the first to look at the effects of reducing the doses of Gardasil, which protects against four strains of HPV, the virus that causes genital warts and cervical cancer, to see whether the vaccine still is effective, the authors wrote. More studies are needed before the recommendations for vaccine doses should be changed, said Simon Dobson, the study’s lead author.
“The public-health question is, is there enough information in this study to say that a two-dose schedule for young girls is all right. The answer is, ‘Not quite yet,’ ” said Dobson, a clinical associate professor in pediatric infectious diseases at BC Children’s Hospital at the University of British Columbia in Vancouver.
HPV is the most common sexually transmitted infection and is the main cause of cervical cancer, according to the U.S. Centers for Disease Control and Prevention. About 12,000 U.S. women get cervical cancer each year.