Utilizing Global Surveillance to Develop a Syphilis Vaccine

Arlene Seña, MD, MPH, became involved in public health and sexually transmitted infections (STIs) out of a desire to serve disadvantaged populations.

“Sexually transmitted infections are actually the most reportable communicable disease among most disadvantaged persons,” said Seña, explaining, “STIs…essentially affect those who are racial and ethnic minorities, also young persons and those who have limited access to care.”

Sena is a professor of medicine in the University of North Carolina (UNC) Division of Infectious Diseases. She is co-project director of a cooperative research grant for a Treponema pallidum vaccine development initiative and a global clinical research consortium.

Seña has over 20 years of STI research experiences, and she specifically studies syphilis, one of the oldest known STIs.

She emphasized that it is vital for clinicians to understand how syphilis presents, and outlined the several stages of the infection.

After a primary infection, appearing as painless genital ulcers, syphilis can spread to a rash, swollen lymph nodes, hair loss, or even hepatitis. At these stages, a person may not know they have syphilis, which is why it’s so important to know the signs and get tested.

After these initial stages, there is a period of latency with no symptoms. Eventually, the infection will present as neurosyphilis, affecting the cerebrospinal nervous system (CNS). At its most severe, syphilis at these stages can affect the cardiovascular system.

In the US, syphilis is still a concern. Since 2000, there has been a steady increase in syphilis infections.

Seña noted that syphilis can be transmitted to infants, calling congenital syphilis “a major concern.” She said that from 2016 to 2020, congenital syphilis cases increased 254%.

Seña’s work often takes a global approach, however, as there are 7 million new cases of syphilis each year. After receiving a research grant a few years ago, Seña and her team are conducting syphilis vaccine research in Malawi, China, and Columbia.

The goal of this research is to determine the strains and genomic sequences of Treponema pallidum bacteria responsible for syphilis infections worldwide. The most prevalent strains will then be used to develop potential vaccine candidates.

In addition to determining the strain composition, Seña and her team are researching the human response to a syphilis vaccine candidate. Finally, they are planning to assist in a national biorepository, hoping to contribute specimens for future syphilis diagnostics.

There are treatments for syphilis, such as penicillin. However, the continued escalation in cases proves a need for educational and preventative measures. “We really need a vaccine…an effective vaccine,” Seña said, “in order for us to really make a dent in the number of cases occurring worldwide.”