A Surprisingly Successful HPV Vaccine A vaccine to protect teenage girls against dangerous strains of the human papillomavirus, or HPV, that are a leading cause of cervical cancer has proved to be enormously effective. A study published Wednesday by the Centers for Disease Control and Prevention found that the prevalence of high-risk strains in teenage girls dropped by half after the vaccine was introduced in 2006, from 7.2 percent in 2006 to 3.6 percent in 2010. Unfortunately, many parents still resist having their daughters immunized. A study published in March found that 44 percent of parents said in 2010 that they did not intend to vaccinate their daughters, up from 40 percent in 2008. Some parents fear that vaccination might promote promiscuity (the new study found no sign of that); some see no need to vaccinate girls before they become sexually active, even though vaccination beforehand offers the best protection. Health officials were surprised at the steep decline in infection rates because only about a third of American teenage girls have received the full course of three doses. In other advanced countries and even in a developing nation like Rwanda, vaccination rates have reached 80 percent or higher. Increasing the vaccination rate to 80 percent in this country could prevent an additional 53,000 cervical cancers and 17,000 deaths among girls now 13 years old and younger over the course of their lives. Doctors need to recommend, and parents need to accept, a vaccine that can save thousands of lives.