The optimal age for U.S. residents to receive a one-time HIV test is 25, according to a new modeling study that took into account identifying undiagnosed cases of the virus as well as cost-effectiveness. This recommendation does not apply to those at high risk for the virus, including men who have sex with men, people who inject drugs and their sex partners, sex workers and the sex partners of people with HIV, all of whom should get tested routinely.

Currently, the Centers for Disease Control and Prevention (CDC) recommends that all Americans receive an HIV test at least once between ages 13 and 64.

Publishing their findings in the Journal of Infectious Diseases, researchers at the CDC and Massachusetts General Hospital (MGH) in Boston conducted a modeling study based on new HIV diagnoses in 2013 as well as individuals’ HIV disease stage upon diagnosis that year. The study authors simulated cases of theoretically HIV-negative 12-year-olds who did not have identifiable risk factors for the virus. Then they modeled a one-time HIV test, costing $36, at age 15, 18, 21, 25 or 30, each of which was implemented in addition to existing U.S. screening practices, in which 30 percent of individuals are tested for the virus by age 24.

Between 2009 and 2013, the HIV diagnosis rate among those ages 13 to 30 was highest among those in the 22-to-25 age bracket.

The investigators concluded that adding a one-time test at age 25 would be the most effective at identifying people living with HIV as well as improving overall health outcomes among young adults while at the same time remaining cost-effective. Specifically, such a measure would cost $96,000 per year of life saved—just below the $100,000 threshold below which such an expenditure is typically considered cost-effective in the United States.

“We began by thinking that if people are screened only once, it makes sense to get screened after the age when the most new HIV infections occur,” study head Anne Neilan, MD, MPH, of the MGH Division of Infectious Disease, said in a press release. “We also thought that if we accounted for all of the HIV testing that is already taking place in the U.S., an additional screening test for youth without known risk factors would be most useful at some point after age 18.” 

“For young people who become infected by age 25, the gains in life expectancy and improvements in health outcomes, including viral suppression, from that one-time screening test would be substantial,” Andrea Ciaranello, MD, MPH, of the MGH Division of Infectious Disease and a senior author of the study, said in the same press release.

The benefits of the one-time test, the study authors stressed, are contingent upon the newly diagnosed people being effectively linked to medical care for the virus and remaining in care.

To read a press release about the study, click here.

To read the study abstract, click here.