Eight times more American young adults now take medication to protect them from HIV than a decade ago, a study finds.

But even with this positive news about increasing use of pre-exposure prophylaxis or PrEP, the study also suggests that health care providers and public health agencies could do more to promote consistent use of these medications.

The study, done by a team at the University of Michigan Medical School, uses national pharmacy data to look at prescriptions for oral PrEP from 2016 to 2023 among people ages 18 to 25. 

It’s published in the Journal of General Internal Medicine. 

At the start of the study period, 26 of every 100,000 U.S. young adults filled a prescription for PrEP, but this rose to more than 208 by the end of 2023.

Prescription dispensing was lower for those ages 18 to 21 than for those ages 22 to 25. 

However, the length of time that a person kept refilling their prescription dropped by more than two weeks during this time.

This may suggest inconsistent use of PrEP, or trouble keeping up with the regular appointments and tests needed to continue the medication.  

We’re encouraged to see more prescribing over time, but the question remains: are we getting it to the highest risk patients?"

-Nina Hill, M.D. 

It’s the first large study to focus just on this age group, which has an especially high risk of HIV transmission. 

PrEP, when taken consistently and as prescribed, can reduce the chances of acquiring HIV through sex by 99%.

It’s also an age group that doesn’t see the doctor often, notes Nina Hill, M.D., the lead author of the study.

Hill is a general internist and pediatrician at U-M, a National Clinician Scholar at the U-M Institute for Healthcare Policy and Innovation, and a postdoctoral fellow in the Susan B. Meister Child Health Evaluation and Research Center.

“This is a patient population we often neglect in health care, because we we don’t think about them belonging to pediatric care or adult care, and their stage of cognitive development means they underestimate their STI risk in general -- yet they’re one of the highest risk groups for a new diagnosis of HIV,” she said.

“We’re encouraged to see more prescribing over time, but the question remains: are we getting it to the highest risk patients?”

She notes the number of steps needed to get to consistent PrEP use: getting screened by a provider or online screening tool to determine if PrEP is appropriate, seeing a provider for the initial exam and tests for HIV and other sexually transmitted infections, receiving and filling a prescription, and keeping up with regular tests of kidney function, HIV and other STIs every three to six months.

Even patients who decide to take their PrEP pills on an episodic rather than daily basis – before time periods when they will be sexually active with new partners, for instance – need to have consistent access.

Either way, she says, it’s important for young adults, their health care providers, and the adults they trust most to discuss their sexual health, and to be aware of the availability of PrEP and its power to prevent HIV.

More about the findings

In all, Hill and her colleagues looked at 1.45 million prescriptions dispensed to nearly 240,000 young adults with an average age of 22. Most (87%) were male, but Hill notes that certain women are also at risk for HIV and might be eligible for PrEP.

Just over a third of the young adults taking PrEP lived in the southern U.S., an area where HIV transmission is especially high.

And the rate of PrEP dispensing started lowest but rose fastest in this region during the study period.

The study covers a period when the first PrEP medication, introduced in 2012 under the brand name Truvada, also became available as a generic drug in 2020, and a second oral PrEP option called Descovy went on the market in 2019.

Though an injectable form of PrEP received approval in 2021, few young adults received this treatment so they were excluded from the study.

More than 70% of the prescriptions during the study period were for Truvada or its generic equivalent.

Hill and her colleagues also looked at what kind of health care provider prescribed PrEP to each person who filled a prescription.

Nurse practitioners accounted for 39% of prescriptions, with family medicine or general practitioners accounting for 22%, and internal medicine physicians and physician assistants accounting for 14% and 11%, respectively.

Although emergency medicine physicians accounted for a very small percentage overall, the number of prescriptions written by them increased tenfold during the study period.

PrEP has been recommended since 2019 by the U.S. Preventive Services Task Force for adolescents and adults who have an increased risk of acquiring HIV.

All individuals should be screened for HIV at least once in their lifetime between ages 15 and 65 years.

Under the Affordable Care Act, most insurance programs must make PrEP and HIV screening available to patients at no cost if they meet USPSTF criteria.

However, the status of that coverage is the subject of a case called Braidwood v. Kennedy that was recently heard before the U.S. Supreme Court; a ruling is expected soon.

More information about PrEP is available via the HIV.gov site.

Additional authors: Hill and senior author Kao-Ping Chua, M.D., Ph.D., and their co-author Sijia He, M.S., are part of the Susan B. Meister Child Health Evaluation and Research (CHEAR) Center, which Chua directs.

Funding/disclosures: Hill is supported by the National Clinician Scholars Program, the Susan B. Meister Child Health Evaluation and Research Center, and a training grant (T32HS000053) from the Agency for Healthcare Research and Quality.

Paper cited: “National Trends in HIV Pre-Exposure Prophylaxis Dispensing to Young Adults, 2016–2023,” Journal of General Internal Medicine. DOI:10.1007/s11606-025-09574-8

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