Megan Bullard, 20, left, of Chelsea, Vt., grimaces as Vermont Rep. Rachel Weston, 25, D-Chittenden, right, of Burlington, Vt., holds hands with Alexandra MacLean, 24, center, of Montpelier, Vt., as Weston receives a vaccine against cervical cancer during the 2nd annual HPV and Cervical Cancer Reception and Dinner, Wednesday, Feb. 21, 2007, in Montpelier. (AP Photo/Alden Pellett) It’s only been a few years since researchers and public health officials determined that just two doses of the HPV vaccine , instead of three, are sufficient to protect people from the infection that can cause multiple cancers and genital warts, as long as they receive the vaccine in early adolescence. Now evidence is accumulating that suggests even one dose is enough. A study from Australia found high levels of protection in women who received only one dose of the HPV vaccine. Past research has already conclusively shown that three doses of the HPV vaccine are highly effective in protecting against ...