Disease Experts See Syphilis Diagnosis as Time to Re-engage in HIV Care
A recent analysis investigated the relationship between HIV and syphilis—specifically, to find out what syphilis infection may mean for people with HIV in terms of HIV viral load and risk of transmission.
“There have been outbreaks of syphilis in multiple urban areas in the last ten years, and we continue to have high rates of syphilis among men who have sex with men. In some cities, more than half of new syphilis infections are among men with HIV. We wanted to investigate what viral loads are like close to the time of syphilis acquisition,” said lead author Melanie Taylor, MD, MPH from the Centers for Disease Control and Prevention.
Both HIV and syphilis are “reportable” infections—all new cases are documented and reported to public health departments. Taylor and colleagues analyzed HIV and syphilis surveillance registry data from New York City, Washington D.C., Philadelphia and Phoenix.
Over two years, 3,060 cases of syphilis were reported. More than half (1,675) of the people who tested positive for syphilis had a match in the HIV surveillance registry (i.e., they had already been diagnosed with HIV). Among all co-infected people, 86% (1,442) were men who have sex with men.
Most of those who were co-infected reported an HIV viral load collected within six months of their syphilis diagnosis—over half of the sample had a detectable viral load. (The median viral load was 25,101 copies/ml3 and viral loads ranged from 206 – 3,590,000 copies/ml3 around the time when participants were infected with syphilis.) Younger people co-infected with HIV and syphilis were more likely to have detectable HIV viral loads: 81.9% of people ages 17–24 had detectable viral loads while 49.2% of people ages 35–44 were detectable.
The concern, said Taylor, is that people living with HIV who have higher viral loads and are having sex in a way that enables them to get infected with syphilis. “For public health, we need to bring attention and services to our HIV-infected patients who get STDs—syphilis, but also rectal and urethral gonorrhea and chlamydia and hepatitis C. We need to focus on getting these people’s viral loads to undetectable.”
Other links between HIV and syphilis are well-established. Physiologically, syphilis sores make it more likely that a person will be infected with HIV if they’re exposed to the virus. And behaviorally, condomless sex can be a risk factor for HIV, syphilis, and other sexually-transmitted infections.
“The extent of HIV coinfection among syphilis cases suggests that the time of syphilis diagnosis is an important moment to evaluate for HIV infection (if current status is unknown), relink to HIV care as needed for syphilis patients with preexisting HIV infection, and emphasize adherence to effective ART,” the authors conclude.
Recent estimates indicate that 60% of people living with HIV in the United States are not engaged in HIV care. “Part of the challenge for health providers and community organizations is locating people with HIV who are not currently in care and getting them connected to the medical system,” said Julie Lifshay, director of health navigation services at San Francisco AIDS Foundation. “Some of the work we’re doing at San Francisco AIDS Foundation is to find and identify people who have fallen out of care. Diagnosing someone with HIV who is out care with an STI is a ‘linkable moment’—an opportunity to talk about HIV, the health benefits of ART, and the importance of staying on treatment, as well as to address any potential barriers to care.”
Taylor, M. and others. Viral Loads Among HIV-Infected Persons Diagnosed With Primary and Secondary Syphilis in 4 US Cities: New York City, Philadelphia, PA, Washington, DC, and Phoenix, AZ. JAIDS, 2015.
AIDS.gov. HIV Care Continuum. Retrieved from: https://www.aids.gov/federal-resources/policies/care-continuum/
Read more about the work San Francisco AIDS Foundation is doing to reach people with HIV and bring them back into care on the San Francisco AIDS Foundation website.