Dr. Justin Radolf

UConn Health Leads Search for Syphilis Vaccine

Dr. Juan Salazar, left, and Dr. Justin Radolf in Radolf's lab at UConn Health in Farmington.

Dr. Juan Salazar, left, and Dr. Justin Radolf in Radolf's lab at UConn Health in Farmington.


While cases of syphilis in Europe first were recorded over 500 years ago, no vaccine candidates have ever advanced to human clinical trials. A new, international center led by the UConn School of Medicine and Connecticut Children’s aims to change that.

UConn will receive up to $11 million over five years from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), to develop a vaccine for this centuries-old disease.

Syphilis poses serious health consequences internationally and in the United States. The World Health Organization (WHO) estimates that 10.7 million people between the ages of 15 and 49 had syphilis in 2012, and about 5.6 million people contract it every year.

“An effective syphilis vaccine would represent a triumph for biomedical research over an ailment that has defied conventional public health strategies for prevention and control,” says Dr. Justin Radolf, professor of medicine and pediatrics at UConn School of Medicine and co-principal investigator with Dr. M. Anthony Moody of Duke University. “If successful, the scientific and public health impact of our approach will extend well beyond syphilis and establish a model to tackle other pathogens.”

Syphilis is primarily transmitted through direct contact with an infectious lesion during unprotected sex, and can also be passed from expecting mothers to their unborn children. Syphilis is the second leading cause of stillbirth and miscarriage worldwide. If left untreated, it can cause strokes, dementia, and other neurological diseases in any infected person.

Past attempts to control the syphilis epidemic by treating infected individuals and their partners have proved unsuccessful, largely due to difficulties diagnosing the disease, limited access to care for certain high-risk individuals, and limited resources for effective contact investigation. Furthermore, syphilis and HIV are recognized as “syndemics,” in which both infections can increase the risk of acquisition and transmission of the other.

The international study team comprises researchers from UConn School of Medicine; Connecticut Children’s; the Duke Human Vaccine Institute; the University of North Carolina (UNC) at Chapel Hill Institute for Global Health and Infectious Diseases; UNC Project-Malawi; Masaryk University in the Czech Republic; and Southern Medical University in Guangzhou, China.

“This center combines the unique capabilities of UConn Health’s Spirochete Research Lab with the rest of the study team, which has world-class vaccine research infrastructure, international health expertise, and unparalleled knowledge of bacterial genomics to achieve our long-term objective,” says Dr. Juan Salazar, chair of pediatrics at UConn Health and physician-in-chief at Connecticut Children’s.