Is it Cost Effective to Preemptively Treat People at High Risk of HIV Infection?

*Updated on 12/12/2016 at 11:43 AM EST

Although big advances in antiretroviral therapies (ART) have kept the number of new HIV infections steady for the past decade, there are still two million new cases worldwide.

According to the Centers for Disease Control and Prevention (CDC), there were approximately 40,000 new cases in the United States last year. A disproportionate share of these new cases occur in men who have sex with men (MSM), African Americans, and adults between the ages of 30 and 64. To address any confusion on how best to treat people with HIV as well as those who are at highest risk of contracting it (such as those in the above cohorts), a group of researchers at the University of Southern California, the University of California, Berkeley, and the RAND Corporation decided to create a mathematical model that shows the cost effectiveness of various HIV treatment protocols.

One treatment protocol, referred to in the study as the “status quo,” involves an individual beginning ART only after he/she has been diagnosed with HIV and has a white blood cell count below 500. This protocol reflects the CDC’s pre-2010 treatment recommendations for HIV. Another treatment protocol is known as “test-and-treat,” which involves testing a patient for HIV and immediately beginning ART if the patient tests positive, no matter what his white blood cell count is. PrEP, short for preexposure prophylaxis, is a newer treatment that involves taking a daily cocktail of drugs designed to prevent HIV in people who are at high risk of infection, such as those who regularly have unprotected sex with HIV-positive individuals or those who use intravenous drugs.

Based on existing population and demographic data, life insurance tables, and HIV surveillance reports, the study authors simulated the incidence of HIV transmission over a period of years among MSM, ages 15 to 65 who live in Los Angeles. They discovered that, compared with the status quo, the least expensive treatment protocol is test-and-treat, coming in at $19,302 per quality-adjusted life year (QALY), if the sample population is tested for HIV every 4 years. The cost would rise to $20,451 per QALY if the men are tested every 3 years, and bump up to $38,492 per QALY if they’re tested yearly. Slightly pricier is the PrEP strategy, which involves giving high-risk men a course of PrEP every 4 years. This strategy costs $27,863 per QALY compared with the status quo. Combining PrEP with various iterations of expanded testing or test-and-treat increases the costs proportionately.

“Given that the current cost of full treatment with three antiretrovirals is more than $15,000 per year, and there are costs for monitoring and treatment is lifelong while PrEP is only needed during the periods of risk, certainly appropriate use of PrEP can be cost effective,” said Kenneth H. Mayer, MD, a professor at Harvard Medical School. “PrEP use is increasing progressively, with more than 80,000 Americans having initiated the medication.” According to Dr. Mayer, provider surveys indicate an increased usage in urban areas, particularly those that have substantial, educated gay communities.

With this rise in use, some practitioners are hopeful that the cost will decline because soon, the original drugs used for PrEP will no longer be subject to patent restrictions. “Other drugs for prevention, like tenofovir alafenamide (TAF) and cabotegravir, are currently under study and could have fewer side effects ... or be given as an injection once every eight weeks,” Dr. Mayer says. “The data from these trials will not be available for more than a year since the studies are just getting underway. New options could be expensive, but availability of generic older drugs could reduce costs--so [there are] many variables to follow over the next few years.”

Extra costs aside, there is no question that more aggressive and earlier treatment strategies can be effective in preventing new HIV infections. The difficulty now is for practitioner health departments to determine the optimal treatment protocol while keeping economics in mind. In a commentary published along with the original study in Clinical Infectious Diseases, authors Kenneth H. Meyer, MD, and Douglas S. Krakower, MD, professors at Harvard Medical School, noted that the healthcare community also needs to focus on expanding testing to more people on a more frequent basis, as 15% of HIV-infected people don’t know that they’re infected, and 30% of those who do know their status are not being treated with ART. This translates into more than 500,000 people who could potentially transmit the virus to their partners.

Due to the fact that some of the people at highest risk of contracting HIV may be reluctant to visit doctors or to reveal their true sexual or drug-related behavior, it remains a challenge for clinicians to identify them so that they may be offered PrEP, the authors said. “Given that the CDC estimates that more than 1 million Americans could benefit from PrEP, there is still a long way to go in terms of provider and community education,” Dr. Mayer said.

Laurie Saloman, MS, is a health writer with more than 20 years of experience working for both consumer and physician-focused publications. She is a graduate of Brandeis University and the Medill School of Journalism at Northwestern University. She lives in New Jersey with her family.