A study involving gay men in Thailand found no evidence that having a sexually transmitted infection (STI) renders a person less likely to have an undetectable HIV viral load than an undetectable person without an STI, reports aidsmap.com.
In other words, STIs do not change the message behind “Undetectable = Untransmittable” (“U=U”), which is that people with HIV who maintain an undetectable viral load cannot transmit HIV sexually. It had previously been thought that STIs might increase the possibility of HIV transmission even when a person is undetectable. That is not the case, as the Thailand study shows. The findings were published this month in the Journal of the International AIDS Society (you can read the article in full here).
However, researchers did find high rates of STIs as well as high rates of HIV; the STI rates remained high throughout the study, which lasted up to 24 months after recruitment. What’s more, researchers also found higher viral loads in the blood and semen and rectal secretions of people who were diagnosed with HIV and STIs but had not yet started HIV meds. The researchers noted that antiretroviral treatment suppressed HIV in all three compartments (blood, semen and rectal) by 12 and 24 months.
As aidsmap points out, these findings show that although STIs might not alter the U=U message, STIs may increase the speed at which the virus may be transmitted by people who have undiagnosed HIV or don’t adhere to treatment.
For the study, researchers followed 143 gay men who tested positive for HIV out of a group of 492 gay men and transgender women. Study participants were enrolled in four clinics in Thailand as part of the Test and Treat Demonstration Project.
At the beginning of the study, 106 people tested positive for HIV (21.5 percent). During the two-year period, an additional 37 people contracted HIV. In total, 133 people started HIV treatment during the study; adherence was over 95 percent.
Regarding STIs, 52 percent of the participants had an STI at the study’s beginning, or baseline. Specifically, 33 percent had chlamydia, 23 percent had gonorrhea and 16 percent had syphilis.
Researchers found that during the 12- and 24-month follow-up, the participants who had STIs were no more likely to have a detectable viral load than the other men. Just one example from several in the study: Five of the 114 people at the one-year follow-up had a detectable viral load. Two of them had STIs; three of them did not.
All five of these men, aidsmap points out, had been cured of syphilis when the study began. It is possible that STIs did not cause the detectable viral load but rather that the presence of STIs and poor adherence were indicative of other challenges these individuals faced that might have affected their viral loads, such as depression or emerging drug resistance to an HIV treatment regimen.
Also worth noting, according to aidsmap, is that the predominant strain of HIV in Thailand is the CRF-AE subtype, thought to be more virulent than other strains.
In their conclusion, the researchers said the findings highlight the importance of scaling up global efforts to roll out treatment as prevention among men who have sex with men. They also stressed the need to include testing for STIs in those efforts.