STI Vaccine development


Syphilis is the second leading cause of stillbirth globally and, if left untreated, can cause brain damage, blindness and paralysis in adults

A successful proof-of-concept study in an animal model suggests that a vaccine to prevent syphilis infection is feasible. Researchers are currently pursuing a two-pronged approach that would reduce syphilis transmission and also prevent the dissemination of syphilis bacteria through the bloodstream, to stop it from causing congenital infections and neurological damage.

An estimated 7 million syphilis infections occur each year, including nearly 1 million among pregnant women. These infections result in more than 350,000 adverse birth outcomes, including 200,000 stillbirths and newborn deaths.

Syphilis can lead to serious and permanent problems like brain damage, blindness and paralysis, as well as prematurity, low birthweight, neonatal death, and infections in newborns.

Syphilis can be cured with a single injection of antibiotics, but many people with syphilis have no immediate symptoms and do not know they are infected and need testing and treatment.

WHO’s Roadmap identifies additional important next steps, including:

  • Attracting new investigators to syphilis vaccine research, which is currently being conducted by only a limited number of scientists
  • Continued sequencing of circulating syphilis strains to provide information on the cross-protective potential of selected vaccine targets
  • Studies investigating immune correlates associated with protection from syphilis
  • Mathematical modeling to predict the global health impact of a syphilis vaccine

Learn More:

WHO syphilis page

Cameron CE. Syphilis Vaccine Development: Requirements, Challenges, and Opportunities. Sex Transm Dis. 2018 Sep;45(9S Suppl 1):S17-S19. doi: 10.1097/OLQ.0000000000000831.