This Week in HIV Research: There’s No Such Thing as Too Much Data
Data are the lifeblood of science. Our cumulative collection of information courses through the veins of medical practice and research, sustaining it, nourishing it, helping it grow and evolve. The flow never stops—and we never stop needing more of it. Every new drop of accurate, peer-reviewed information adds to our ability to understand and fight disease.
In this week’s tour of recently published HIV-relevant research with potential clinical implications, we take a look at four new sets of valuable data:
- An all-too-rare glimpse into epidemiological factors among transgender women.
- A revised estimate of the number of U.S. men who have sex with men (MSM) who likely meet pre-exposure prophylaxis (PrEP) indications.
- Intriguing trends in HIV strain similarity between younger and older MSM.
- The monumental impact of widely available direct-acting antivirals on the hepatitis C epidemic among British MSM living with HIV.
Into these data we go. To beat HIV, you have to follow the science!
Research Explores Factors Affecting HIV Incidence Among Trans Women
Among transgender women, HIV seroconversion risk is associated with younger age, being a person of color, and structural factors, according to a small study in San Francisco, California, published in Journal of Acquired Immune Deficiency Syndromes.
The study involved 377 participants over an 18-month span. With eight seroconversions over 604 person-years of follow up (PYFU), the overall HIV incidence rate was 1.3/100 PYFU. But it was significantly higher among participants who were 18-24 years old compared to older participants. Incidence was also higher among trans Latinx women and women of color.
While the data should not be overinterpreted given the small number of HIV acquisitions, they do show the importance of addressing seroconversions in marginalized communities if the U.S. wants to achieve its goal of ending the domestic epidemic by 2030, study authors stated.
Also of note: The HIV incidence rate within the study rose to 2.3/100 PYFU among participants who had been previously in jail or prison, and to 5.8/100 PYFU for those without health insurance. “History of incarceration and lack of health insurance point to structural drivers of continued HIV acquisition among trans women that must be addressed,” the study authors wrote.
More MSM Meet PrEP Indications Than Previously Estimated
Roughly 180,000 more MSM in the U.S. meet indications for PrEP than the Centers for Disease Control and Prevention has estimated, according to an analysis of results from a web-based convenience sample of 3,511 sexually active, HIV-negative MSM that was published in the Journal of Acquired Immune Deficiency Syndromes.
In 2015, the CDC estimated that 25% of all MSM in the U.S. might benefit from PrEP. But in 2017, PrEP guidelines were updated to somewhat loosen guidelines regarding key indications. The current study, conducted between 2017 and 2019, found that 34% of MSM met PrEP indications based on the 2017 guidelines.
The new analysis also included an alternative approach to data classification: The 2015 CDC analysis counted as “HIV negative” anyone who did not report that they were living with HIV, but the current study only considered people to be “HIV negative” if they actually reported being HIV negative.
Most young participants did not know their HIV status, which may explain the low perceived PrEP eligibility rates among that group. Eligibility was also low among Black men, possibly because seroconversion rates in that community are relatively high, leaving fewer HIV-negative men who may benefit from PrEP.
HIV in Young MSM of Color Increasingly Linked to Virus in Older Men
Genetic transmission research indicates that in recent years, younger MSM living with HIV in the U.S. have increasingly begun to harbor viral strains that are closely related to those found in older MSM, a study published in Journal of Acquired Immune Deficiency Syndromes showed.
Overall, the virus of 37% of 9,510 MSM aged 13-24 years in 17 U.S. jurisdictions was genetically linked to someone at least 5 years older than them.
Comparing people diagnosed between 2009 and 2012 and between 2013 and 2016, that linkage to older partners increased among young Black and Latino men. Among MSM between 13 and 19 years old, the adjusted prevalence ratio for such related virus was 1.31 for Latino men and 1.23 for Black men compared to white men. Among MSM between 20 and 24, the ratio was 1.14 for Black men compared to white men.
The study authors cautioned that a close relationship between viral strains does not indicate that direct transmission occurred between the two people with those similar strains, nor does it indicate the direction of transmission.
Still, the findings are intriguing in light of the recent increase in the use of mobile apps to find romantic partners. While such apps existed in the study’s early time period (2009 to 2012), they only became popular in the later period (2013 to 2016), researchers noted. “Success in increasing the percentage of older MSM with HIV who are aware of their infection and virally suppressed is likely to have benefits not only for their health but also in reducing HIV transmission involving younger MSM,” they concluded.
HCV Incidence Declined Sharply in UK After DAAs Became Available
In the United Kingdom, hepatitis C incidence rates among MSM and who are living with HIV dropped sharply after their peak in 2015, just before direct-acting antivirals (DAAs) became widely available through the country’s National Health Service (NHS), researchers reported in Clinical Infectious Diseases.
The retrospective cohort study at five urban HIV clinics found 378 acute HCV infections, 292 of which were first infections, between 2013 and 2018. The highest incidence rate, at 14.6/1,000 PYFU, was recorded in 2015. Incidence dropped to 4.6/1,000 PYFU in 2018. HCV reinfections appeared to hold relatively steady from the beginning to the end of the study period.
The study also found a dramatic scale-up of early HCV treatment initiation among the study population. In 2013, at the beginning of the study period (and prior to the regular availability of DAAs), the average gap between HCV diagnosis and treatment initiation was 30 months. By 2018, the gap had shrunk to four months.
In the UK, NHS rules do not allow for DAAs before six months of persistent viremia (among people with chronic infection) nor in case of reinfections, the authors of the current study noted. “Our data suggest that access to earlier public sector treatment than is currently available, including for reinfection, will remain important to ensure progress to microelimination targets in MSM living with HIV,” they concluded.