According to a new study, PrEP is safe for use by gay and bisexual teen boys.

The study, published in JAMA Pediatrics, is among the first to investigate the safety and efficacy of PrEP for males age 15 to 17.

Men who have sex with men in that age cohort are among the most at risk of contracting HIV. But PrEP, been found to be more than 90% effective at reducing the risk of infection, is currently only FDA-approved for use by adults.

Researchers at Stroger Hospital in Chicago plan to submit their data to the FDA in hopes of extending it to younger at-risk communities.

“I think the safety piece is important,” lead researcher Sybil Hosek told Reuters. “It was well tolerated. We didn’t see many complaints about side effects. We did not see many adverse events.”

The trial involved 78 gay and bi young men between the ages of 15 and 17 in six U.S. cities. At the beginning of the study, all of the participants tested negative for HIV, and received 48-weeks-worth of daily doses of PrEP, as well as counseling about HIV risk.

A total of 47 participants completed the study, and only three adverse effects possibly related to PrEP were reported. Addressing a common concern, researchers noted they did not see any increase in risky sexual behaviors during the course of the trial.

Three of the young men participating in the study did become infected with HIV during the course of the trial, but blood samples suggest that they were taking less than two doses of PrEP a week, rather than the prescribed seven doses.

It isn't uncommon for adolescents to have trouble adhering to daily medication regimens. Hosek's team admitted that would be a key issue in ensuring PrEP's efficacy among at-risk youths, should the FDA agree with their recommendations.

“Adolescents may require additional visits than what is currently recommended by national guidelines," wrote Dr. Renata Arrington-Sanders in an editorial accompanying the report, as well as "a need for multiple team members to address structural barriers to accessing PrEP, assist with youths’ interpretation of HIV risk, and support self-efficacy to swallow and adhere to medications."

The rate of new HIV infections in the study was 6.4 cases per 100 people per year, which is about twice as high as the rate for 18-22-year-olds in a similar trial. Said Hosek, “I shudder to think what the rate would be if we didn’t offer PrEP,”