Preteen boys and girls might only need two doses of the vaccine against human papilloma viruses (HPV) instead of three, health officials now say.

The decision was made by members of an Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention (CDC), who met Oct. 19 in Atlanta.

Officials would ideally like to see kids get the vaccine age 11 or 12, before they become sexually active.

But CDC officials observed that fewer than a third of 13-year-olds in the U.S. get all the necessary shots to protect them. Concerned about the underuse of an important cancer preventative tool, the panel is now recommending preteens get fewer shots spaced six to 12 months apart in an attempt to make the vaccination process easier.

“It will be simpler now for parents to get their kids the HPV vaccine series, and protect their kids from HPV cancers,” Nancy Messonnier of the CDC said in a press release.

The vaccine protects against HPV, which can cause cervical cancer, genital warts, and other types of cancer. It is commonly spread through sex, but in most cases the virus doesn’t cause any problems. However, common infections might trigger the virus to attack.

But a vaccine that was costly for those whose insurance plans didn’t cover it and that required three doses within six months was often a problem for busy parents. The move also aims to raise languishing HPV vaccination rates that have been dropping since the vaccine went on sale a decade ago.

“I know people who say ‘I can’t do that. Why even start?’” said Cynthia Pellegrini, a March of Dimes official who is on the panel.

The decision was based on recent studies showing that two doses of the only currently marketed HPV vaccine, Gardasil 9 – Merck’s Gardasil 9 is the only one of three vaccines that remains on the market – worked just as well in children from 9 to 14 years old.

The study was followed by a U.S. Food and Drug Administration (FDA) confirmation that the vaccine could be safely administrated in two doses instead of three, and two doses worked better when spaced six to 12 months apart.

The panel advises that three doses should still be taken by teens who don’t get their first shot until they are 15 years old. But those who can switch to two doses can now receive their vaccines at annual check-ups, within a year of the first vaccine.

HPV vaccines were first recommended for girls in 2006, and then for boys in 2011, mainly to reduce the spread to girls – for whom the virus is really threatening. But with the very slow rise in vaccination rates, health officials are wondering how to reverse that trend and get more teens and preteens to make use of this easy cancer prevention tool.

One of the main concerns doctors and parents have about promoting the vaccine is they don’t want to be seen as giving their approval for kids to start having sex. Doctors also said the three-part vaccine schedule didn’t help.

“I think it was the icing on the cake [for parents already hesitant about the vaccine]”, said William Schaffner, a Vanderbilt University vaccine expert.