While the availability of HIV treatments in the late 1990s dramatically improved survival, they also contributed to a resurgence in syphilis, a sexually transmitted infection.
This is according to a study, “Unintended Consequences of Life-Saving Pharmaceutical Innovations: How HAART Led to the Resurgence of Syphilis” by David Beheshti, Scott Cunningham and Nir Eilam, that was published in Health Economics.
Through statistical analyses of information from the Centers for Disease Control, as well as pharmaceutical industry sales data, the researchers found that locations with higher AIDS prevalence experienced significantly larger increases in syphilis after highly active antiretroviral therapy (HAART) became widely available — with these increases concentrated among men, while rates among women continued to decline — suggesting that changes in sexual behavior following the reduced perceived risk of HIV had broader public health effects.
According to the researchers, “the introduction of HAART was partially responsible for the resurgence of syphilis”, with the resurgence appearing to be driven by two main factors: changes in higher-risk sexual behavior and increased longevity among a particularly high-risk group (MSM living with HIV).
“The perceived reduction in the severity of HIV due to HAART likely encouraged an increase in higher-risk sexual behaviors, such as unprotected sex. Additionally, the extended lifespan of people living with HIV contributed to a larger and more sexually active population, which may have facilitated the spread of other STIs such as syphilis.”
Data indicated that in the absence of HAART, there would have been 81% fewer syphilis cases between 1996 and 2008.
So for the researchers, “the resurgence of syphilis underscores the importance of anticipating and addressing potential behavioral responses to medical innovations.”
“With syphilis now at a 60‐year high, these findings offer timely insight into how life‐saving innovations can reshape population behavior and highlight the need for complementary public‐health strategies,” said co-author Beheshti of the University of Texas at San Antonio.
