CDC: Highlights from The 2016 Conference on Retroviruses and Opportunistic Infections

The annual Conference on Retroviruses and Opportunistic Infections (CROI 2016) took place in Boston, Massachusetts earlier this week at the Hynes Convention Center. CROI is the premier international venue for bridging basic and clinical investigation to clinical practice in the field of HIV and related viruses. Top scientists, clinicians, and policy makers from around the world had the opportunity to share with each other the latest studies, important developments, and best research methods in the ongoing battle against HIV and AIDS and related infectious diseases.croi-boston

The Centers for Disease Control and Prevention scientists presented more than 40 abstracts that highlighted new HIV research findings and its implications for HIV prevention efforts across the nation. Symposium and plenary lectures, workshops, themed discussions, and oral presentations are available online as webcasts. (You can also follow CDC highlights from CROI on Twitter @CDC_HIVAIDS or #CROI2016 to see conversations from this year’s conference.)

Studies that may be of particular interest to readers are briefly summarized below.

Estimating the Lifetime Risk of a Diagnosis of HIV Infection in the United States. Study authored by Kristen Hess, Xiaohong Hu, Amy Lansky, Jonathan Mermin, and H. Irene Hall

This study presents the first-ever comprehensive national estimates of lifetime risk of an HIV diagnosis by race/ethnicity, geographic area, and risk group for all 50 states and the District of Columbia. Using mortality, census, and HIV surveillance data from 2009-2013, the authors estimate 1 in 99 people will receive a diagnosis of HIV infection during their lifetime, a decrease of 22% from a previous study that analyzed data from 2004-2005. Despite overall progress, this study reveals vast disparities among race/ethnicity, sexual risk, age, and geographic location:

  • By risk group, men who have sex with men (MSM) continue to face the greatest burden of HIV.

    • At current rates, an estimated 1 in 6 MSM will be diagnosed with HIV in their lifetime, nearly 80 times more likely than for heterosexual men.

    • The risk also varies considerably by race and ethnicity—1 in 2 black MSM, and 1 in 4 Latino MSM will be diagnosed with HIV in their lifetime, compared to 1 in 11 white MSM.

  • African Americans remain the most affected racial or ethnic group, with 1 in 20 men, and 1 in 48 women at risk for HIV in their lifetime.

  • People who inject drugs are at much higher risk than the general population, with 1 in 23 for women, and 1 in 36 for men.

  • By region, people living in the Southern U.S. face the highest risks for HIV, including Washington, D.C. (1 in 13) and the states of Maryland (1 in 49), Georgia (1 in 51), Florida (1 in 54), and Louisiana (1 in 56).

While lifetime risk has decreased compared to previous estimates, continued improvements in HIV prevention and treatment are needed. The data on lifetime risk may help to communicate the risk of HIV infection to affected communities and increase public awareness of HIV.  

Impact of Improving HIV Care and Treatment and Initiating PrEP in the U.S., 2015-2020. Study authored by Emine Yaylali, Paul G. Farnham, Evin Jacobson, Stephanie L. Sansom, et al.

The authors developed a dynamic model of HIV transmission that shows dramatic reductions in new HIV infections are possible by 2020, if the National HIV/AIDS Strategy (NHAS) goals of increasing diagnosis, care, and treatment for people living with HIV, and scaling up the use of PrEP* are met. The results show thousands of new HIV infections can be averted in different scenarios:

  • As many as 185,000 infections can be prevented if we reach national targets for HIV testing, and treatment, while scaling up PrEP:

    • Meeting the NHAS 2020 target of increasing the percentage of people living with HIV who are diagnosed to 90% and the percentage of persons with an HIV diagnosis who are virally suppressed to 80%, could prevent 168,000 new HIV infections.

    • Rapid uptake of PrEP can help prevent another 17,000 new HIV infections by 2020, if 40% of high-risk MSM, 10% of injection drug users, and 10% of high-risk heterosexuals used PrEP.

  • If current rates of diagnosis, care, and treatment are maintained from 2015 – 2020:

    • More than 265,000 new infections could occur over that period without PrEP.

    • The addition of PrEP would help prevent more than 40,000 cases by 2020.

Findings from this study highlight the promising outcomes of expanding testing, treatment, and PrEP and reaching the NHAS goals. While the model offers an encouraging glimpse into the future, more work remains to accelerate access to testing, treatment, and PrEP uptake over the next five years.

The Evolving Epidemiology of HIV Infection in Persons Who Inject Drugs: Indiana 2015. Authored by Dr. John Brooks

HIV infections attributable to injection drug use in the U.S. have declined steadily since the early 1990s and have accounted for less than 8% of all diagnosed infections since 2010. However, there is a growing national epidemic of opioid drug abuse and injection drug use – heralded by viral hepatitis C infections – that is beginning to spread among populations not previously considered to be at high risk of HIV infection. In 2015, a small rural county in southeastern Indiana detected an outbreak of HIV infections within a network of persons who injected drugs. This plenary highlighted how county, state, and federal partners worked closely with the community and other stakeholders to control the outbreak, and how to prevent potential outbreaks of HIV infection associated with injection drug use among populations not previously considered to be at high risk for HIV infection. Dr. Brooks also provided an overview of how to recognize and respond to an outbreak following CDC’s experience and lessons learned in responding to the HIV outbreak in Indiana. Clinicians and public health authorities will need to work together with policy makers and at-risk communities to prevent similar future HIV outbreaks as the context of injection drug use in the U.S. evolves.

Missed Opportunities for HIV Testing During Routine Doctor Visits, BRFSS, 2011-2013. authored by Michelle Van Handel and Patricia Dietz

Using data from the 2011-2013 Behavioral Risk Factor Surveillance System, the authors found that nearly 100 million adults ages 18 to 64 had never been tested for HIV, and more than half had missed an opportunity for HIV testing during a recent routine doctor visit. The percentage of people who missed a testing opportunity increased from 62 percent in 2011 to 64 percent in 2013. The study also shows that in 2013:

  • Women, aged 45-64, and non-Hispanic whites accounted for the highest percentage of people with missed opportunities for HIV screening.

  • People living in the Eastern and Southern regions of the United States had higher rates of having recently missed an opportunity for HIV screening, compared with other regions of the nation.

  • Individuals with health insurance coverage accounted for almost 90 percent of people who missed opportunities for HIV screening. 

The analysis draws attention to current gaps in routine HIV testing and the need for all providers and local health authorities to increase routine HIV screening rates, and follow CDC testing recommendations. CDC recommends that individuals aged 13-64 get tested at least once in their lifetimes and those with factors get tested more frequently. Both CDC and the United States Preventive Services Task Force advise clinicians to screen for HIV among all adolescents and adults, regardless of risk.

Setting a Benchmark for HIV Testing at Visits to U.S. Physician Offices by men aged 18-39 years. Authored by Karen Hoover, Charles Rose, and Philip Peters

This analysis estimated the frequency of HIV testing among men ages 18 to 39 at physician office visits using data from the 2009-2012 National Ambulatory Medical Care Survey. The findings highlight how infrequently adult men are tested for HIV during outpatient physician appointments in the United States:

  • Men ages 18-39 were tested for HIV at only 1.3 percent of an estimated 58.4 million annual doctor’s visits.

  • Among those aged 18 to 24, Hispanic and black men had fewer annual physician visits than white men. However, among those who did have an annual physician visit, Hispanic and black men were more likely than white men to be tested for HIV.

  • At current testing rates, less than half of all black men and less than a third of Hispanic and white men would be tested for HIV by age 39.

The authors conclude that a four-fold increase in HIV testing at routine doctor visits would help achieve significant increases in testing among all groups—moving closer to CDC’s HIV testing recommendation that everyone between the ages of 13 and 64 gets tested for HIV at least once as part of routine health care. 

Increased HIV Viral Suppression Among US Adults Receiving Medical Care, 2009-2013. authored by  Heather Bradley, Christine L. Mattson, Linda Beer, Ping Huang, and Luke Shouse

The Medical Monitoring Project (MMP) is a surveillance system that adds to the range of information that is collected through CDC’s National HIV Surveillance System (NHSS). The authors used 2009-2013 MMP data to estimate the proportion of persons receiving HIV medical care who achieved viral suppression (<200 copies/ML) at both last test and at all tests in the previous 12 months. Sample data were collected from 23,125 persons using interviews and medical record abstractions:

  • From 2009 to 2013, the proportion of people who were virally suppressed increased from 72% to 80%.

  • The positive trend was seen among non-Hispanic blacks, non-Hispanic whites, and Hispanics; and MSM.

  • The largest increases were seen among 18-29 year olds (56% to 68%); 30-39 year olds (62% to 75%), and non-Hispanic blacks (64% to 76%).

Findings suggest persons receiving HIV medical care are increasingly likely to achieve viral suppression. Efforts to engage persons living with HIV in medical care and promote antiretroviral therapy (ART) may be contributing to these increases. CDC uses NHSS data as the primary source to monitor progress towards the National HIV/AIDS Strategy: Updated to 2020 goal of increasing the percentage of persons with diagnosed HIV infection who are virally suppressed to at least 80%.

Chemoprophylaxis with Oral FTC/TAF Protects Macaques from Rectal SHIV Infection. Authored by Ivana Massud, James Mitchell, Frank Deyounks, Walid Heneine, J. Gerardo García-Lerma, et al.

The authors investigated whether the combination of tenofovir alafenamide (TAF)*** and tenofovir (FTC)**** could prevent rectal SHIV (simian-human immunodeficiency virus) infection in rhesus macaques monkeys to a degree similar to that of FTC/TDF. To do so the authors followed two phases: phase I consisted of a single dose pharmacokinetic study to identify a human-equivalent dose of TAF in macaques; phase II consisted of a proof-of-concept PrEP study with FTC/TAF using a validated repeat low virus dose SHIV transmission model. Results showed that FTC/TAF prevents rectal SHIV infection in macaques to a degree similar to that previously found with FTC/TDF but with a substantially reduced dose. As expected, low TAF doses result in high intracellular TFV-DP concentrations in peripheral blood mononuclear cells with levels that exceed those previously seen with oral TDF. The studies’ results suggest that FTC/TAF may be a feasible alternative to FTC/TDF for PrEP against rectal HIV infection. However, FTC/TAF should not be used in humans until clinical studies are complete and it is approved for a PrEP indication.

* Pre-Exposure Prophylaxis (PrEP) is a once-daily pill regimen that can help you stay HIV-negative. Post-Exposure Prophylaxis (PEP) is an HIV prevention strategy that involves taking HIV medications immediately after a possible exposure to HIV. It takes a few days for HIV to become established in the body following exposure. When taken as PrEP, HIV medications block the virus from making copies of itself and spreading throughout the body. People who use PrEP must commit to taking the drug every day and seeing their healthcare provider for follow-up appointments and testing. When taken as prescribed, PrEP has been shown to be more than 90 percent effective against contracting HIV. PrEP is much less effective if it is not taken daily. PrEP is considered fairly safe, and the regimen is generally well-tolerated. The pill used for PrEP, Truvada, has been used to treat people living with HIV since 2004. PrEP can cause mild side effects, including upset stomach, headaches and weight loss, especially at the beginning of the regimen. Rare side effects include kidney or bone problems. Talk to a knowledgeable healthcare provider if you are especially concerned about side-effects.

***Tenofovir alafenamide is an investigational drug that is being studied for the treatment of HIV infection. It is also being studied for the treatment of chronic hepatitis B virus (HBV) infection. Tenofovir alafenamide belongs to a class (group) of HIV drugs called nucleoside reverse transcriptase inhibitors (NRTIs). NRTIs block an HIV enzyme called reverse transcriptase. (An enzyme is a protein that starts or increases the speed of a chemical reaction.) By blocking reverse transcriptase, NRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body. It is a prodrug, which means that it is an inactive drug. Once taken, a prodrug does not work until the body converts it into an active form. In the body, tenofovir alafenamide is converted to tenofovir diphosphate (TFV-DP). Studies suggest that tenofovir alafenamide may be more effective against HIV and cause fewer side effects than the FDA-approved NRTI tenofovir disoproxil fumarate (brand name: Viread).

**** Tenofovir (FTC), also known as Truvada, is a fixed-dose combination tablet combining 200mg FTC (emtricitabine) and 245mg tenofovir. It is manufactured by Gilead Sciences. FTC is a nucleoside reverse transcriptase inhibitor (NRTI) and tenofovir is a nucleotide reverse transcriptase inhibitor (NtRTI). These drugs reduce the amount of HIV in the body. The standard dose of Truvada is one tablet once a day, with or without food, in combination with at least one other anti-HIV drug. It is licensed for use in adults over 18 years of age. Its European license was granted in February 2005 and it was licensed in the United States in August 2004.

The approval of Truvada was based on studies showing that taking the combination tablet produced levels of FTC and tenofovir that are similar to the constituent drugs of tenofovir (Viread) and FTC (Emtriva) taken separately, as well as on studies showing the effectiveness of the two drugs. The safety, resistance, and effectiveness of the combination were also extrapolated from previous studies of tenofovir and 3TC (lamivudine, Epivir). Emtricitabine is regarded as sufficiently similar to 3TC by regulatory authorities that it could be treated as a substitute for the purposes of approval.

The 48-week data presented from the HEAT study in 2008 showed that safety, efficacy, and side-effect profiles of Kivexa and Truvada (emtricitabine/FTC + tenofovir) had similar rates of viral suppression and were well tolerated. Truvada’s constituent drugs have not been assessed in pregnant women, so it is not recommended for use during pregnancy unless the potential benefit outweighs the risk.

The annual Conference(s) on Retroviruses and Opportunistic Infections (CROI) will be held next February 13-17, 2016 in Seattle, Washington and March 4-7, 2018 in Boston, Massachusetts.