STI Surveillance Network (SSuN)

Key points

The STI Surveillance Network allows CDC and state and local health departments to better understand the epidemiology of sexually transmitted infections (STIs) nationally and locally to inform prevention efforts.

Overview

The purpose of the STI Surveillance Network (SSuN) is to:

  • Provide enhanced behavioral, demographic, and clinical information on gonorrhea and early adult syphilis cases reported to state and local health departments.
  • Provide information on patients presenting for care in specialty STI clinical settings.
  • Explore innovative strategies to improve STI surveillance nationwide.

SSuN is a collaboration of competitively selected state, county, and city health departments, funded to provide a better understanding of national, state, and local STI epidemiology. Established in 2005, SSuN is currently in the fifth cycle. The current cooperative agreement for activities ongoing through 2025 is CDC-RFA-PS-24-0082.

Strategies

There are three (two core and one optional) SSuN surveillance strategies, each addressing different methods of enhanced STI surveillance. Cycle 5 awardees have been funded for Strategy A, Strategy B, or both

Strategy A

Strategy A of SSuN Cycle 5 provides support for selected health departments to implement sentinel surveillance in specialty STI clinics. Funded sites gather information on patient visits, including STI/HIV tests performed at the visit, test results, diagnoses made, and demographic and selected behavioral characteristics of the patients. This strategy provides data on patients seeking sexual health care, provider testing and treatment practices, changes in the number and proportion of patients diagnosed with STIs and HIV co-infection, and uptake of prevention measures such as HIV pre-exposure prophylaxis (PrEP) and doxycycline post-exposure prophylaxis for STIs (doxy PEP).

Strategy B

Strategy B of SSuN Cycle 5 collects enhanced information on all reported cases of gonorrhea and syphilis. This includes information on laboratory results, treatment, and outcomes from routine partner service interviews. Additionally, all funded sites randomly sample reported gonorrhea and syphilis cases in their jurisdictions for enhanced clinical, treatment, and behavioral investigations. This provides a probability sample of cases that are weighted to represent all reported cases in the participating sites. Enhanced investigations provide valuable information on gender of sex partners and HIV prevention measures, such as HIV PrEP and doxyPEP use, and Mpox vaccination status.

HIV Surveillance Registry Matching‎

All patients attending participating specialty STI clinics in Strategy A, as well as all reported gonorrhea and syphilis cases in Strategy B, are matched against the sites' HIV surveillance registry. This allows for analysis of HIV prevalence among persons diagnosed and reported with selected infections and among persons seeking care in specialty STI clinics.

Strategy C

No Strategy C projects were funded for SSuN Cycle 5.

Through this combination of collaborative surveillance activities, SSuN provides comprehensive information to supplement what CDC receives via routine national case reporting. This information provides CDC and collaborating health departments with STI-related healthcare and incidence trends not currently available from any other source.

This page includes additional information about SSuN data collection protocols, participating jurisdictions, recent publications, and contact information for SSuN project officers.

Currently Funded SSuN Cycle 4 Collaborators (2024 – 2029)