All sexually active adolescents should be screened for HIV, the American Academy of Pediatrics said Monday in a new policy statement that broadens earlier recommendations.

And in areas with higher rates of the infection, all teens over 16 should get the test, the group added in its statement.

More than 1.1 million Americans are infected with HIV, and 55,000 of them are between 13 and 24 years old.

"Forty-eight percent of the youth who are infected don't know they are infected," said Dr. Jaime Martinez of the University of Illinois in Chicago, who helped write the new report, published in the journal Pediatrics.

"It's important to realize that those who don't know they are infected drive the epidemic," he told Reuters Health.

HIV usually proceeds to AIDS in the absence of treatment, but newer drugs can keep that from happening for many years. And knowing you're infected may also help stem transmission of the disease to others—a benefit that isn't seen with cancer screening, for instance.

Today, many doctors only offer testing to patients they deem at risk, such as prostitutes, drug addicts and homosexual men. But since 2006, the U.S. Centers for Disease Control and Prevention have urged everybody older than 13 to get an HIV test regardless of risk factors in areas with many undiagnosed cases.

The new statement is a bit more conservative, said Martinez, lest pediatricians be uncomfortable testing younger teenagers. He added that in 12th grade, more than 60 percent of adolescents say they are sexually active—and that often they're having sex while under the influence.

An HIV test costs about $14, according to Martinez, and is accurate more than 99 percent of the time. Overall, less than one percent of the tests sound a false alarm.

Martinez acknowledged that a few people might be treated without harboring the virus, but added that even if the first test is positive, it still needs to be confirmed by a second before a diagnosis is made—so the odds of treating someone mistakenly are very small.

"I hope pediatricians will feel comfortable offering this test," he said.

But not all experts are convinced screening everybody is the way to go.

Last week, a large study from French hospitals showed more than 1,000 adults would need to be tested for HIV to find just one new infection, making the researchers question routine screening.

Given similar low yields from other studies, the government-backed U.S. Preventive Services Task Force makes no recommendations to the general public about HIV screening, although it urges high-risk groups to get screened.

Dr. Jason Haukoos at the Denver Health Medical Center is among the critics of sweeping screening programs.

"There is reasonable evidence to support screening, but it is not clear what the best approach is," he told Reuters Health. "I think the policy statement is a reasonable statement, but I say that recognizing that they don't take it far enough in terms of how this should be done."

For example, he said, there are still questions about consent and disclosure when it comes to children. And it's unclear who would pay for the extra screening.

"The big issue here is, we don't know if it's cost-effective," Haukoos said.