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When it comes to the vaccine against human papillomavirus (HPV), there’s good news but also some news that’s concerning.

On the positive side, a new analysis of 26 studies has confirmed that the vaccine is up to 99 percent effective at preventing the development of several types of abnormal cervical cells that can progress to cervical cancer. Other recent research has found that the number of people getting the vaccine is on the rise.

But the overall numbers of people vaccinated against HPV are still too low. And according to a new study in the American Journal of Public Health, fewer people may be finishing the series of shots.

Not getting all the recommended doses of the vaccine (two or three, depending on age) or waiting more than a year between doses could be a problem, says study author Jennifer Spencer, a PhD candidate at the University of North Carolina at Chapel Hill.

At age 11 or 12, children should get two shots of the HPV vaccine six to 12 months apart, according to the Centers for Disease Control and Prevention. Those who are 15 or older when they begin the series need three shots within six months for full protection.

In 2006, according to the new study, 67 percent of girls and young women who started the HPV vaccine series had completed the shots within a year. But by 2014, just 38 percent had done so.

That may be because some doctors don’t consider completing the series as important for patients as other issues, Spencer says. Also, doctors might not see kids this age in a timely manner. Adolescents may be less likely than younger children to go to a doctor for a yearly checkup.

But it is important, experts say. HPV, which often shows no symptoms early on, is responsible for 90 percent of all cervical and anal cancers, CDC statistics show, as well as a large share of cancers of the vagina, penis, vulva and throat. In total, HPV causes about 31,500 cancers in the United States each year.

“Every parent should make it a priority to get their child — girl or boy — vaccinated against HPV,” says Consumer Reports’ medical director, Orly Avitzur. “The vaccine provides a window of opportunity to prevent HPV-related cancers in adulthood.”

Here’s what else you need to know about the HPV vaccine, and how to make sure kids and teens finish the series.

Vaccination rates are better

The federal government’s official goal is to have 80 percent of girls and boys ages 13 to 15 receive all necessary doses of the vaccine by 2020. According to a March study in the Journal of Infectious Diseases, just 27.4 percent of boys and men ages 9 to 26 reported receiving at least one dose of the vaccine in 2015 or 2016. That’s up from just 7.8 percent a few years prior. For girls and women, 45.7 percent had at least one dose of the vaccine in 2015 or 2016.

U.S. rates of HPV infection remain high. An April 2017 report from the National Center for Health Statistics found that 25 percent of men and 20 percent of women ages 18 to 59 are infected with what’s called high-risk HPV, the type that can cause cancer.

Completing the series

Research has shown that primary-care physicians don’t recommend the HPV vaccine as strongly as they do other vaccines for adolescents, in large part because it takes longer to discuss and they perceive that parents don’t support it for their kids. So if your doctor doesn’t bring up the HPV vaccine, ask about it.

To make it easier for your youngster to finish the series, schedule an appointment for the next dose right after he or she gets the first, Spencer says. Or ask your doctor’s staff to send you a reminder notice. A 2016 study found that not receiving a reminder was a key reason parents forgot to take kids to finish the HPV vaccine series.

If your child hasn’t received the first dose at age 11 or 12, you have some time. It’s best for people to get the HPV vaccine before they become sexually active because the vaccine is somewhat less effective once people have been exposed to the virus.

But it’s still recommended until age 21 for men and age 26 for women, as well as for men who have sex with men and a few other specific groups, the CDC says.

 Copyright 2018, Consumer Reports Inc.

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