The US Preventive Services Task Force (USPSTF) published updated recommendations on screening for syphilis on September 27.1 The Task Force continues to recommend screening for all adolescents and adults who are at increased risk for infection. (As part of previous recommendations, the USPSTF also advocates screening all pregnant women for syphilis early in their pregnancy to prevent congenital syphilis.2)
Who is at increased risk? Men who have sex with men (MSM), those with HIV or other sexually transmitted infections (STIs), those who use illicit drugs, and those with a history of incarceration, sex work, or military service are considered to be at increased risk for syphilis. Additionally, since state and local health departments collect and publish STI incidence data, it’s important to stay up to date on how common syphilis is in one’s community and tailor screening practices accordingly.
Men account for more than 80% of all primary and secondary syphilis infections, and MSM account for 53% of cases in men.3 The highest rates of syphilis are in men ages 25-29 years and 30-34 years (58.1 and 55.7 cases per 100,000, respectively).3
Why screening is important. Primary and secondary syphilis rates have increased steadily from an all-time low of 2.1 per 100,000 in 2000 to 12.7 per 100,000 in 2020.4 There were 171,074 cases reported in 2021.5
If not detected and treated, syphilis will progress from the primary and secondary stages to a latent form. About one-third of those with latent syphilis will develop tertiary syphilis, which can affect every organ system and cause multiple neurologic disorders.
How to screen. Syphilis screening typically involves a 2-step process. The first test that should be performed is a Venereal Disease Research Laboratory (VDRL) or rapid plasma reagin (RPR) test. This is followed by a treponemal antibody test if the initial test is positive. While the VDRL and RPR tests have high sensitivity, many other conditions can cause a false-positive result, necessitating confirmation with the more specific antibody test.
As far as frequency, the Task Force suggests screening annually for those at continued risk and more frequently (every 3 or 6 months) for those at highest risk.
Treatment for primary, secondary, and early latent syphilis (< 1 year’s duration) is a single intramuscular (IM) injection of benzathine penicillin, 2.4 million units. For late latent syphilis or syphilis of unknown duration, treatment is benzathine penicillin, 2.4 million units, administered in 3 weekly IM doses.
Treatment for those with penicillin allergies depends on the stage of syphilis and whether or not the patient is pregnant. Refer to the STD treatment guidelines for guidance.6
The CDC recommends presumptive treatment for anyone who has had sexual contact in the past 90 days with a person who’s been given a diagnosis of primary, secondary, or early latent syphilis.6
And finally, remember that all STIs are reportable to your local health department, which can assist with contract tracing and treatment follow-up.