This Week in HIV Research: A Bite of the Apple

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You know the old adage, "An apple a day keeps the doctor away?" Quaint though it is, you probably know as well as we do the broader truth underlying it: Preventive medicine is often good medicine. Yet in the U.S., as in much of the world, we live largely in a treatment-focused area; the value of knowledge and prevention tends not to gain as much traction as it may be due.

These days, what conversation we do have about HIV prevention tends to revolve around pre-exposure prophylaxis (PrEP). But there's so much more to pay attention to when it comes to preventing HIV transmission as well as HIV treatment failure, as this week's selection of recently published research attests:

  • Housing stability needs to be closely examined and addressed to curb the risk of HIV viremia.
  • The stigma of poverty, as much as poverty's direct effects, can impair viral suppression.
  • Syringe services could prevent hundreds of HIV infections if implemented before a rural outbreak occurs.
  • The relatively unused practice of index testing could greatly improve HIV status awareness worldwide.

Let's do what we can to stay up to date on research like this and carry the torch for preventive health. To beat HIV, you have to follow the science!

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Unstable Housing Is Important Factor in Viremia Among Women

Two-thirds of women highly likely to be viremic were unstably housed, a longitudinal study published in JAMA Network Open found.

Researchers analyzed 23 years of data on 1989 people enrolled in the Women’s Interagency HIV Study (WIHS) in Chicago, New York (Brooklyn and Bronx Counties), San Francisco, and Washington, D.C. Modeling identified three trajectories: low (29% of participants), intermediate (39%), or high (32%) probability of viremia (defined as having a viral load > 200 copies/mL).

The proportion of viremic women dropped in all groups over time, partly due to changes in treatment guidelines and the recent availability of more effective regimens. In the most recent time period, spanning 2015 to 2017, 90% of participants in the low-probability group were virally suppressed, compared to 83% in the intermediate-probability group, and 35% in the high-probability group.

Participants in the high-probability group were more likely to be unstably housed (66% of the 637 women in that group), suffer from depression, and report current drug and alcohol use compared to women in the other two groups.

Study authors called for further research that includes other geographic locations, as well as identification of replicable programs to improve sustained viral suppression rates.

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Stigma Attached to Poverty Impacts Viral Suppression Rates in Women

The experience of poverty stigma, beyond actual socioeconomic disadvantages, is associated with a lower likelihood of viral suppression, a study published in AIDS showed. Poverty stigma is the belief that low-income people are lazy and immoral because they could be better off financially if they worked harder, study authors explained.

The researchers analyzed data from a WIHS substudy that, unlike the longitudinal study summarized in our previous item, included participants in the U.S. South. The 433 participants were mostly middle-aged women of color. Fifty-seven percent reported an annual household income of $12,000 or less, 7% reported unstable housing, and 1.1% the experience of poverty stigma.

Overall, 69% of participants were virally suppressed (< 20 copies/ml), 84% reported at least 95% treatment adherence, and the same percentage had CD4 cell counts ≥ 350 cells/µl. Poverty stigma reduced the likelihood of viral suppression (adjusted odds ratio = 0.76), but taking all medications as prescribed at least 95% of the time mediated the effect of that stigma.

Study authors called for more research and the development of interventions for reducing poverty stigma.

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Proactive Syringe Services in Rural U.S. May Most Effectively Prevent HIV

Implementing a syringe services program before HIV is introduced into a network of people who inject drugs is the most effective way to prevent an outbreak of the virus, a modeling study published in Clinical Infectious Diseases showed.

The model estimated that, without a syringe program, the introduction of one seroconversion into a network of people who inject drugs would result in 210 new HIV acquisitions over five years. By comparison, if a program were started after the first 10 HIV diagnoses, 91 seroconversions would occur during the same period; and if a syringe exchange already existed before the first seroconversion is introduced, 32 people would acquire HIV within five years of that initial HIV case.

The model used data from Scott County, Indiana, where an outbreak occurred in 2014-2015. The study focused only on averting HIV infections, but syringe programs also provide other harm-reduction services, including overdose prevention and linkage to substance use treatment, which extends their public health benefits, study authors noted. They called for implementing syringe services programs in rural areas vulnerable to HIV outbreaks before such outbreaks occur.

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Index Testing Can Diagnose Many Who Are Unaware of Their HIV Status

Globally, utilizing the practice of index testing greatly increased successful HIV diagnoses relative to other testing approaches, a study published in Mortality and Morbidity Weekly Report found.

Researchers analyzed HIV testing data from 20 countries supported by the U.S. Centers for Disease Control and Prevention. During the study period (2016-2018), 66 million tests were administered, 2.4% of which were index tests -- i.e., HIV testing of sexual partners and biologic children of people living with HIV.

Overall, the study found that 4.1% of people age 15 years or older, and 1% of children under 15 years old, were diagnosed with HIV. Those rates increased, however, when isolated to include only index testing, which accounted for a small proportion of the total number of tests. Among people 15 and older, 9.8% of HIV diagnoses were the result of index testing; the proportion was 1.5% for children.

Index testing was found to be particularly effective as a method of reaching men, as well as people in the 25-to-49 age group. "Scaling up index testing as part of the overall HIV testing services strategy could help increase the number of HIV-positive persons who know their status, are initiated onto antiretroviral treatment, and consequently reduce the number of persons who can transmit the virus," study authors concluded.