Is HIV Medication Responsible for Syphilis in the Gay Community?
For the past few years, health authorities have become increasingly concerned about rising rates of syphilis, particularly among gay and bisexual men. Now, a new study suggests that one contributing factor might be antiretroviral medication taken to combat the progression of HIV.
In September of 2016, the CDC released figures showing that between 2013 and 2014 men who have sex with men (MSM) experienced an 8.8 percent rise in syphilis infections across several U.S. states. But this alarming fact wasn’t completely unprecedented.
Rates of several other STIs, including antibiotic resistant gonorrhea have increased dramatically, but the rise in syphilis appears to predominantly affect the MSM community.
What’s more, the U.S. isn’t alone in suffering this health problem. Several other countries including the UK, China and regions of Latin America have reported rising syphilis rates.
Some have blamed the rise of hookup apps like Grindr for this increase, but the research isn’t convincing. Others — usually anti-LGBT forces — have been quick to blame MSM themselves, saying they are acting irresponsibly by having unprotected sex. Clinicians have also pointed to risky sexual behavior, but they’ve admitted that further study is needed, as this doesn’t seem to be the only contributing factor.
Thus, researchers have been keen to investigate precisely why syphilis appears to affect the gay and bisexual community more than other population groups. And they now have identified one possible answer: HIV medication.
Antiretrovirals may exacerbate syphilis rates
On the face of it, claiming that HIV medication leads to higher STI rates doesn’t seem to make sense. Highly active antiretroviral therapy, or HAART, is considered the primary weapon against the progression of HIV-1 infections, and the drugs actually boost a person’s immune system. This means that people taking this course of treatment should be less likely to fall prey to bacterial infections like those that cause syphilis.
However, researchers have been aware of an emerging trend for some time now: Syphilis appears to affect HIV-positive people in the gay and bisexual community more than those without the virus. That trend suggests a possible overlap and was the basis of a study conducted by researchers from Canada and South Africa.
Michael Rekart, professor at the UBC School of Population and Public Health, explained:
After reading about the astounding increase in syphilis cases, I also noticed a huge gap between syphilis and other sexually transmitted infections like chlamydia and gonorrhea. That led me to believe there must be something else going on.
The study reviewed existing data on HIV infection and immune response, and researchers used two distinct mathematical models to predict syphilis rates. One model relied on the premise that risky sexual behavior was to blame for the rise in syphilis. The other model took into account the possibility that HAART medication may have created a susceptibility to the bacteria that leads to syphilis.
A pattern quickly emerged. While each model on its own predicted an outbreak of syphilis, it wasn’t until the researchers examined both models together that they could find figures that closely predicted outbreaks in British Colombia, as well as other regions. As to why HAART might cause this problem — and why it seems to specifically apply to syphilis — the researchers have a theory.
A BMJ press release summarizes:
The body’s clearance of T pallidum [the bacteria behind syphilis] relies on an increase in the number of an immune system cell called a T cell and a cascade of chemicals that stimulate an inflammatory response. HAART dampens down these activities. Clearance of chlamydia and gonorrhea is less reliant on these processes.
A theory, not a link
The researchers make it absolutely clear that their hypothesis does not in anyway confirm a link between HAART and the rise in syphilis. In effect, they are simply opening the door and asking for further research on this topic.
Is that warranted, though?
Researchers Drs. Susan Tuddenham, Maunank Shah and Khalil Ghanem from Johns Hopkins University School of Medicine in Baltimore, who were not connected with this study, stated in an adjoining editorial that they believe caution is needed. Syphilis outbreaks have happened before, and they have affected certain populations more than others.
Tuddenham and her fellow analysts also explained that screening procedures emphasizing syphilis over other STIs may make any small disparity appear much larger than it is. Furthermore, infection rates may be increasing more uniformly than data currently suggests.
Nevertheless — and with these caveats in mind — they say that the hypothesis remains intriguing and reasonable based on the findings generated by researchers. Their commentary notes:
We are living in an era where ART is being used to effectively treat and prevent HIV infection. To some extent, this seems to have tempered the urgency to control other STDs. As history has shown many times over, that would be a costly mistake. Over the past 15 years, syphilis rates among MSM have been rising unabated. We are not aware of any recent intervention that has led to a sustained decline in syphilis rates in this population. If further investigations support a role for ART in increasing susceptibility to syphilis, this will provide one more reason why screening, diagnosis and treatment of STIs in MSM must be prioritized.
There is one final takeaway from this research that is absolutely crucial: These findings are not reason for patients to stop taking their HIV medication.
Use of condoms and the employment of safer sex practices can effectively shield most people from STIs, and routine screening can ensure STIs don’t spread. As the researchers themselves put it, HAART saves lives, and syphilis can be treated. This study is just the first step to understanding the cause of the problem.
Photo Credit: James Emery/Flickr