Despite extensive efforts, there’s still no cure for HIV. Since the virus often lives dormant in cells, it’s difficult for doctors to deem a person is cured. But, a newly developed test may be sensitive enough to identify “hidden” HIV, according to research published in Nature Medicine.

The scientists at the University of Pittsburgh who developed the test, also found that the amount of people who are thought to be nearly cured of HIV, is much larger than previous estimates.

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"Globally there are substantial efforts to cure people of HIV by finding ways to eradicate this latent reservoir of virus that stubbornly persists in patients, despite our best therapies," said senior author Phalguni Gupta, in a statement. "But those efforts aren't going to progress if we don't have tests that are sensitive and practical enough to tell doctors if someone is truly cured."

Thanks to the development of antiretroviral therapies, or ART, people with the virus have been able to live significantly longer and healthier lives. Despite the therapy being successful, it’s key to know if the present HIV infected cells have the ability to replicate. Currently, the best available test to detect this is called Q-VOA, which stands for quantitative viral outgrowth assay. Disadvantages of Q-VOA is that it’s costly, requires a large amount of blood, and is time-consuming. Typical costs can be around $1,200, according to Johns Hopkins University.

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Gupta and his colleagues have developed TZA - a test that’s quicker, cheaper, requires less blood, and is less labor-extensive than Q-VOA. TZA works by detecting a gene that is activated only when replicating HIV is present.

"Using this test, we demonstrated that asymptomatic patients on antiretroviral therapy carry a much larger HIV reservoir than previous estimates—as much as 70 times what the Q-VOA test was detecting," Gupta said. "Because these tests have different ways to measure HIV that is capable of replicating, it is likely beneficial to have both available as scientists strive toward a cure."

In the United States, about 1.2 million people are living with HIV, according to the Centers for Disease Control and Prevention. It’s estimated about 1 in 8 of them don’t know it. People who are most affected include young African American gay and bisexual men.

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