A federal advisory committee voted on Tuesday to recommend that boys aged 11 and 12 be vaccinated against human papillomavirus, or HPV, to protect against anal cancer and cancers of the mouth and neck. The new guidance mirrors that for girls aged 11 and 12, who have been advised since 2006 to receive routine HPV vaccinations.
The HPV vaccine is already approved by the government for males aged 9 to 26 to prevent genital warts and anal cancer, but the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) had not issued a formal recommendation for routine vaccination in boys until now.
In part, that’s because when the vaccine was approved for use in boys and men in 2009, there wasn’t enough evidence to justify the cost of population-wide vaccination. The HPV vaccine is expensive, costing hundreds of dollars for the three-dose series.
Since 2009, however, studies have provided additional information on the benefits of vaccinating boys, helping to lead to the ACIP’s current, unanimous decision. In February, for example, researchers reported that the HPV vaccine prevented 90% of genital warts in men who were not infected with the virus before immunization. The vaccine was also found to be 75% effective in protecting against anal cancer in a study of primarily gay men. There is also early evidence that it protects against certain penile and throat cancers, and recent data suggest that HPV is increasingly responsible for some mouth and throat cancers, which have been on the rise — probably because of increasing rates of oral sex.
With 20 million Americans infected with HPV each year, the new recommendations for boys will be an important part of cancer prevention in coming years, according to public health expert. Anne Schuchat, director of the CDC’s National Center for Immunization and Respiratory Diseases told reporters that “Today is another milestone in the nation’s battle against cancer.”
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Now that the CDC’s committee has officially recommended the vaccine for boys, most private insurers are likely to start paying for it.
HPV infection is the most common sexually transmitted disease in the U.S. Most sexually active men and women will acquire the virus at some point in their lives. In most people, infections will clear on their own, but in some, persistent infections can cause genital warts or cancer, including cervical, vaginal and vulvar cancers in women and anal cancer in men. The most widely used HPV vaccine, Gardasil, manufactured by Merck — to which the ACIP recommendation applies — is designed to protect against the four high-risk strains of the virus that contribute to warts and cancer.
For the most part, the ACIP’s advice for vaccination in boys involves the same reasoning behind the recommendation for girls aged 11 to 12: that immunizing youngsters as part of routine childhood vaccination programs — despite the fact that they are not necessarily sexually active or at high risk of HPV infection — ensures that more people will be protected against HPV early on.
Of course, the issue of sexual activity has been the sticking point for many parents of youngsters who are eligible for the vaccine. That concern is largely responsible for low vaccination rates in girls. Despite the data showing that the HPV vaccine prevents cancer, only 44% of girls aged 13 to 17 had received one dose of the vaccine, and only 27% had received all three doses in 2009. The vaccine is supposed to be given before girls become sexually active.
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The low vaccination rates in girls help justify the cost of vaccination in boys. If more males are protected, then they will be less likely to pass the virus to females. “If the boys are also immunized, it reduces the transmission back and forth,” Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt University School of Medicine, who attended the CDC meeting as an adviser but not a voting member, told CNN.
However, some experts expect the vaccine to be an even tougher sell in boys than in girls, in part because anal cancer is relatively rare in men and because most cases are in homosexual men. Some parents may say, “‘Why are you vaccinating my son against anal cancer? He’s not gay! He’s not ever going to be gay!’ I can see that will come up,” Dr. Ranit Mishori, a family practice doctor in Washington, D.C., and an assistant professor at the Georgetown University School of Medicine, who supports the ACIP’s recommendation, told the AP.
For its part, the American Academy of Pediatrics included the HPV vaccine in its schedule of routine vaccinations for 9-to-18-year-olds, released in February.
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Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.