Draft Recommendation Statement
Syphilis Infection in Nonpregnant Adolescents and Adults: Screening
February 15, 2022
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
- Update in Progress for Syphilis Infection in Nonpregnant Adolescents and Adults: Screening
|Asymptomatic, nonpregnant adolescents and adults who are at increased risk for syphilis infection||The USPSTF recommends screening for syphilis infection in persons who are at increased risk for infection. See the Practice Considerations section for information on increased risk.||A|
Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.
Syphilis is a sexually transmitted infection (STI) that can progress through different stages (primary, secondary, latent, and tertiary) and cause serious health problems if left untreated.1 Tertiary syphilis, which occurs in approximately one-third of latent syphilis cases, can affect multiple organ systems.2 Syphilis can attack the nervous system (neurosyphilis) and visual system (ocular syphilis) at any stage of disease resulting in movement disorders, sensory deficits, dementia, paralysis, visual changes, or blindness.1 Syphilis infection also increases the risk for acquiring or transmitting HIV infection.1,3
Primary and secondary syphilis are the most infectious stages of the disease. Reported cases of primary and secondary syphilis in the United States increased from a record low of 2.1 cases per 100,000 population in 2000 and 2001 to 11.9 cases per 100,000 population in 2019. Although men account for the vast majority of cases (83% of primary and secondary syphilis cases in 2019), rates among women nearly tripled from 2015 to 2019. Men who have sex with men are disproportionately affected, accounting for a majority (57%) of all primary and secondary syphilis cases among men in 2019.4 The overall rate of primary and secondary syphilis among men who have sex with men was 106 times the rate among men who only have sex with women and 168 times the rate among women.5 Primary and secondary syphilis rates are highest among Black adolescents and adults, nearly 5 times the rate among White adolescents and adults. Elevated rates have also been reported in Native Hawaiian and Pacific Island adolescents and adults, Native American and Alaskan Native adolescents and adults, and Hispanic adolescents and adults.4 The drivers of this disparity are not well understood but are unlikely to be explained by biology or sexual behavior alone.6,7
In 2016, the U.S. Preventive Services Task Force (USPSTF) reviewed the evidence for screening for syphilis infection in nonpregnant adolescents and adults and issued an “A” recommendation for persons who are at increased risk.9 The USPSTF has decided to use a reaffirmation deliberation process to update this recommendation. The USPSTF uses the reaffirmation process for well-established, evidence-based standards of practice in current primary care practice for which only a very high level of evidence would justify a change in the grade of the recommendation.10 In its deliberation of the evidence, the USPSTF considers whether the new evidence is of sufficient strength and quality to change its previous conclusions about the evidence.
Using a reaffirmation process, the USPSTF concludes with high certainty that there is a substantial net benefit of screening for syphilis infection in nonpregnant persons who are at increased risk for infection.
Go to the Table for more information on the USPSTF recommendation rationale and assessment.
For more details on the methods the USPSTF uses to determine the net benefit, see the USPSTF Procedure Manual.10
Patient Population Under Consideration
This recommendation applies to asymptomatic, nonpregnant adolescents and adults who have ever been sexually active and are at increased risk for syphilis infection.
In this Recommendation Statement, sex and gender as well as race and ethnicity terminology are based on how study participants were reported in reviewed studies. This recommendation is inclusive of all persons at increased risk for syphilis.
Assessment of Risk
The USPSTF recommends screening for syphilis in persons who are at increased risk for infection. When deciding which persons to screen for syphilis, clinicians should consider the prevalence of infection in the communities they serve, as well as other sociodemographic and behavioral factors that may be associated with increased risk of syphilis infection. For example, prevalence of syphilis is higher in males, men who have sex with men, persons living with HIV, young adults, and persons with a history of incarceration, sex work, or military service. Higher infection rates in persons of some racial and ethnic groups have been reported, but more likely reflect a combination of factors, including social determinants of health (e.g., disparities of income, low educational achievement, and unstable housing),6 differential health insurance coverage or access to quality health care,6 and differences in sexual network characteristics (e.g., individuals living in communities with a high prevalence of STIs have an increased chance of encountering an infected partner).7 Local prevalence rates may change over time, so clinicians should be aware of the latest data and trends for their specific population and geographic area, which are available through their state and local health departments and Centers for Disease Control and Prevention (CDC) surveillance.11,12
Although direct evidence on screening in nonpregnant persons who are not at increased risk for syphilis infection is lacking, based on the established test performance characteristics of current screening tests and the low prevalence rate of syphilis in this population, the yield of screening is likely low.11 Therefore, screening in this population may result in high false-positive rates and overtreatment.
Current syphilis screening tests rely on detection of antibodies rather than direct detection of the organism that causes syphilis, Treponema pallidum. A traditional screening algorithm is a two-step process involving an initial nontreponemal test (e.g., Venereal Disease Research Laboratory [VDRL] or rapid plasma reagin [RPR] test) followed by a confirmatory treponemal antibody detection test (e.g., fluorescent treponemal antibody absorption [FTA-ABS] or T. pallidum particle agglutination [TP-PA] test).13 A more recently developed reverse sequence algorithm uses an automated treponemal test (e.g., enzyme-linked or chemiluminescence immunoassay) for the initial screening followed by a nontreponemal test for reactive samples.13 Discordant results in the reverse sequence are resolved with a second confirmatory treponemal test, preferably testing for a different treponemal antibody than the initial test.11 Most laboratories perform traditional screening;14 however, the automated processes used in reverse sequence may be appropriate for high-volume laboratories or areas where populations may be at higher risk for late-stage latent disease that traditional screening may miss.15
Rapid point-of-care (POC) testing for antibodies to T. pallidum can provide quick onsite results (typically within 5 to 30 minutes); however, initial real-world data show sensitivity may be low.16
Optimal screening frequency for persons who are at increased risk for syphilis infection is not well established. Men who have sex with men or persons living with HIV may benefit from screening at least annually or more frequently (e.g., every 3 to 6 months) if they continue to be at high risk.11,17
The effectiveness of parenteral penicillin G for the treatment of primary, secondary, and latent syphilis is well established. Dosage and the length of treatment depend on the stage and symptoms of the infection. Clinicians are encouraged to refer to the CDC’s “STI Treatment Guidelines” for the most up-to-date treatment guidance.17
The USPSTF did not review evidence on screening for syphilis in persons living with HIV or taking HIV pre-exposure prophylaxis if screening was part of disease management. The CDC provides recommendations for these circumstances and other specific groups. The CDC also describes management and followup considerations, including interventions to decrease transmission and reinfection.17
The CDC reports national, state, and local data of reported syphilis infections at https://www.cdc.gov/std/statistics/2019/tables.htm. The CDC also provides more information about STIs, including syphilis, at https://www.cdc.gov/std/default.htm, as well as guidance for clinicians on providing quality STI clinical services, at https://www.cdc.gov/mmwr/volumes/68/rr/rr6805a1.htm.
The National Academies of Sciences, Engineering, and Medicine provides a comprehensive systems-based approach for prevention and control of STIs at https://www.nap.edu/catalog/25955/sexually-transmitted-infections-adopting-a-sexual-health-paradigm.
The Community Preventive Services Task Force has issued several recommendations on the prevention of HIV/AIDS, other STIs, and teen pregnancy. The Community Guide discusses interventions that have been efficacious in school settings, and for men who have sex with men, at https://www.thecommunityguide.org/topic/hiv-stis-and-teen-pregnancy.
Other Related USPSTF Recommendations
The USPSTF has issued a separate recommendation for screening for syphilis infection in pregnant persons,8 as well as screening recommendations for other STIs, including hepatitis B,18 hepatitis C,19 genital herpes,20 HIV,21 and chlamydia and gonorrhea.22 The USPSTF has also issued a recommendation on behavioral counseling for all sexually active adolescents and for adults who are at increased risk for STIs.23
This recommendation is a reaffirmation of the USPSTF 2016 recommendation statement. In 2016, the USPSTF reviewed the evidence for syphilis screening in nonpregnant adolescents and adults and found convincing evidence that the benefits of screening substantially outweighed the harms (“A” recommendation).9 In the current update, the USPSTF found no new substantial evidence that could change its recommendation and, therefore, reaffirms its recommendation to screen for syphilis in nonpregnant adolescents and adults.
Scope of Review
To reaffirm its recommendation, the USPSTF commissioned a reaffirmation evidence update. The aim of evidence updates that support the reaffirmation process is to identify if there is new and substantial evidence sufficient enough to change the prior recommendation.10 The reaffirmation update focuses on targeted key questions evaluating the performance of risk assessment tools and the benefits and harms of syphilis screening in nonpregnant adolescents and adults. The review also included a more limited literature search comparing testing algorithms and the accuracy of rapid POC tests. Because the USPSTF previously determined that treatments for these infections are effective and well established, this review did not include a review of treatments.
Accuracy of Screening Tests and Risk Assessment
Test accuracy can vary based on disease stage. A literature review showed that commonly used nontreponemal tests (RPR, VDRL) have low sensitivity for detecting primary (63% to 78%) and late latent syphilis (61% to 64%) but high sensitivity for detecting secondary (100%) and early latent syphilis (85% to 100%). Sensitivity for treponemal tests is high across the spectrum of disease, ranging from 78% to 100%. Treponemal tests also have high specificity for primary syphilis (87% to 100%).11
There is limited evidence directly comparing the traditional and reverse sequence algorithms. A recent 2020 narrative study reviewed 69 articles summarizing the pros and cons of the two algorithms. Findings showed that the nontreponemal test in the traditional algorithm may have decreased sensitivity for detecting primary and latent syphilis. The automated tests used in the reverse sequence algorithm allows for faster processing but may have higher false-positive rates than the traditional algorithm. The study concluded that the traditional algorithm may be more appropriate for smaller laboratories with lower volumes of testing because performing manual nontreponemal screening assays would not significantly affect workflow. Alternatively, the reverse algorithm may be more suitable for either larger laboratories where automated testing processes can improve workflow and efficiency or for smaller laboratories serving higher-risk populations.15
A 2020 systematic review evaluated rapid POC test performance in laboratory and real-world settings. The study found that the pooled sensitivity from the laboratory evaluations (n=5) was 98.5% (95% CI, 92.1% to 100%), while pooled specificity was 95.9% (95% CI, 81.5% to 100.0%). The pooled sensitivity for prospective studies (n=10) was 87.7% (95% CI, 71.8% to 97.2%), while pooled specificity was 96.7% (95% CI, 91.9% to 99.2%). However, in two of these prospective studies, the sensitivity was only 50%. Differences in testing protocols, training, and specimen collection (e.g., sera vs. whole-blood samples) are potential factors explaining the inconsistency in test performance between laboratory and real-world POC testing.16
The USPSTF reviewed one fair-quality study (n=361) that evaluated an online calculator for predicting syphilis within the next 3 months in high-risk individuals seeking STI testing or treatment in Peru. The model with the greatest area under the curve (0.69) included the following risk factors: current HIV infection, history of syphilis infection, number of male sex partners in past 3 months, and sex role for anal sex (receptive or insertive) in the prior 3 months.24
Benefits of Early Detection and Treatment
The USPSTF reviewed one fair-quality Australian cohort study (n=117,387) examining trends in syphilis testing and detection among sexually active men who have sex with men (68% HIV-negative). During an 8-year followup period, the proportion of men tested for syphilis annually increased significantly among both HIV-negative (n=97,895) and HIV-positive (n=19,492) men (48% to 91% in HIV-negative men and 42% to 77% in HIV-positive men; p trend <0.0001). Syphilis was detected in 2,799 (3%) HIV-negative men and 1,032 (5%) HIV-positive men. The proportion of early latent infections detected increased from 27% to 44% in HIV-negative men and 23% to 45% in HIV-positive men (p trend <0.0001), while the proportion of secondary infections decreased from 24% to 19% (p trend=0.03) and 45% to 26% (p trend=0.0003) in HIV-positive and negative men, respectively. This study demonstrated that screening in men who have sex with men was associated with greater detection of early asymptomatic syphilis and a decrease in secondary syphilis, suggesting that screening is likely to have interrupted the progression of syphilis.25
No studies reported the effectiveness of screening on acquisition or transmission of other STIs or other complications such as tertiary syphilis or neurosyphilis. No studies directly addressed effective screening intervals in the included populations.
The effectiveness of penicillin G for the treatment of primary, secondary, and latent syphilis is well established and was not reviewed for this recommendation update.17
Harms of Screening and Treatment
The USPSTF reviewed one fair-quality, pre-post design study (n=1,097) examining emotional stress associated with rapid POC STI testing. Participants considered to be in high-risk groups completed a questionnaire assessing emotional stress prior to and after testing for HIV, hepatitis C, and syphilis. Factors associated with increased stress included history of injected drug use, Black race, less than a high school education, and single marital status. The study did not compare changes in the levels of emotional stress pre- vs. post-testing.26
Studies are needed that provide more information on the following.
- Validated risk assessment tools, feasible for use in primary care, that will more accurately identify populations at increased risk of infection who would benefit most from screening.
- Direct evidence evaluating the benefits and harms of screening for syphilis in adolescents.
- Factors driving demographic, geographic, and occupational health disparities and effective prevention strategies that may improve health inequities.
- Optimal screening intervals for all high-risk populations.
- Effectiveness of rapid POC testing in real-world settings.
The CDC recommends at least annual screening for syphilis in sexually active men who have sex with men, with confirmatory testing for individuals with reactive serology. The CDC recommends that persons living with HIV who are sexually active be screened at the first HIV evaluation, and at least annually thereafter. Men who have sex with men and persons living with HIV may benefit from more frequent screening (e.g., every 3 to 6 months) based on individual risk behaviors and local epidemiology. The CDC also recommends opt-out syphilis screening in correctional facilities based on the local area and institutional prevalence.17 The American College of Obstetricians and Gynecologists does not recommend routine screening for syphilis in women who are not pregnant.27 The HIV Medicine Association (part of the Infectious Diseases Society of America) recommends that all patients living with HIV be screened for syphilis upon initiation of care and periodically thereafter, depending on risk.28 The recommendation of the American Academy of Family Physicians is similar to the USPSTF guidelines for screening for syphilis in persons at increased risk.29,30
- Centers for Disease Control and Prevention. Syphilis – CDC Fact Sheet (Detailed). https://www.cdc.gov/std/syphilis/stdfact-syphilis-detailed.htm. Accessed January 25, 2022.
- Harvard Health. Syphilis. https://www.health.harvard.edu/a_to_z/syphilis-a-to-z. Accessed January 25, 2022.
- Centers for Disease Control and Prevention. Syphilis & MSM (Men Who Have Sex With Men) – CDC Fact Sheet. https://www.cdc.gov/std/syphilis/stdfact-msm-syphilis.htm. Accessed January 25, 2022.
- Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2019. Atlanta, GA: U.S. Department of Health and Human Services; 2021.
- de Voux A, Kidd S, Grey JA, et al. State-specifc rates of primary and secondary syphilis among men who have sex with men--United States, 2015. MMWR Morb Mortal Wkly Rep. 2017;66(13):349-354.
- Tapp J, Hudson T. Sexually transmitted infections prevalence in the United States and the relationship to social determinants of health. Nurs Clin North Am. 2020;55(3):283-293.
- Newman LM, Berman SM. Epidemiology of STD disparities in African American communities. Sex Transm Dis. 2008;35(Dec):S4-S12.
- US Preventive Services Task Force. Screening for syphilis infection in pregnant women: US Preventive Services Task Force reaffirmation recommendation statement. JAMA. 2018;320(9):911-917.
- US Preventive Services Task Force. Screening for syphilis infection in nonpregnant adults and adolescents: US Preventive Services Task Force recommendation statement. JAMA. 2016;315(21):2321-2327.
- U.S. Preventive Services Task Force. Procedure Manual. www.uspreventiveservicestaskforce.org/uspstf/procedure-manual. Accessed January 25, 2022.
- Henninger MH, Bean SI, Lin JS. Screening for Syphilis Infection in Nonpregnant Adults and Adolescents: A Targeted Evidence Update for the U.S. Preventive Services Task Force. Evidence Synthesis No. 218. AHRQ Publication No. 22-05290-EF-1. Rockville, MD: Agency for Healthcare Research and Quality; 2022.
- Centers for Disease Control and Prevention. Tables: Sexually Transmitted Disease Surveillance, 2019. https://www.cdc.gov/std/statistics/2019/tables.htm. Accessed January 25, 2022.
- Henao-Martínez AF, Johnson SC. Diagnostic tests for syphilis: new tests and new algorithms. Neurol Clin Pract. 2014;4(2):114-122.
- Rhoads DD, Genzen JR, Bashleben CP, Faix JD, Ansari MQ. Prevalence of traditional and reverse-algorithm syphilis screening in laboratory practice: a survey of participants in the College of American Pathologists syphilis serology proficiency testing program. Arch Pathol Lab Med. 2017;141(1):93-97.
- Ortiz DA, Shukla MR, Loeffelholz MJ. The traditional or reverse algorithm for diagnosis of syphilis: pros and cons. Clin Infect Dis. 2020;71(Suppl 1):S43-S51.
- Bristow CC, Klausner JD, Tran A. Clinical test performance of a rapid point-of-care syphilis treponemal antibody test: a systematic review and meta-analysis. Clin Infect Dis. 2020;71(Suppl 1):S52-S57.
- Workowski KA, Bachmann LH, Chan PA, et al. Sexually transmitted diseases treatment guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187.
- US Preventive Services Task Force. Screening for hepatitis B virus infection in adolescents and adults: US Preventive Services Task Force recommendation statement. JAMA. 2020;324(23):2415-2422.
- US Preventive Services Task Force. Screening for hepatitis C virus infection in adolescents and adults: US Preventive Services Task Force recommendation statement. JAMA. 2020;323(10):970-975.
- US Preventive Services Task Force. Serologic screening for genital herpes infection: US Preventive Services Task Force recommendation statement. JAMA. 2016;316(23):2525-2530.
- US Preventive Services Task Force. Screening for HIV infection: US Preventive Services Task Force recommendation statement. JAMA. 2019;321(23):2326-2336.
- US Preventive Services Task Force. Screening for chlamydia and gonorrhea: US Preventive Services Task Force recommendation statement. JAMA. 2021;326(10):949-956.
- US Preventive Services Task Force. Behavioral counseling interventions to prevent sexually transmitted infections: US Preventive Services Task Force recommendation statement. JAMA. 2020;324(7):674-681.
- Allan-Blitz LT, Konda KA, Vargas SK, et al. The development of an online risk calculator for the prediction of future syphilis among a high-risk cohort of men who have sex with men and transgender women in Lima, Peru. Sex Health. 2018;15(3):261-268.
- Chow EP, Callander D, Fairley CK, et al. Increased syphilis testing of men who have sex with men: greater detection of asymptomatic early syphilis and relative reduction in secondary syphilis. Clin Infect Dis. 2017;65(3):389-395.
- Reynolds GL, Fisher DG, Brocato J, van Otterloo L, Khahlil K, Huckabay L. Stressful point-of-care rapid testing for human immunodeficiency virus, hepatitis C virus, and syphilis. Int J STD AIDS. 2017;28(10):975-984.
- Aberg JA, Gallant JE, Ghanem KG, et al. Primary care guidelines for the management of persons infected with HIV: 2013 update by the HIV Medicine Association of the Infectious Diseases Society of America. Clin Infect Dis. 2014;58(1):e1-34.
- American College of Obstetricians and Gynecologists. Chlamydia, Gonorrhea, and Syphilis. https://www.acog.org/womens-health/faqs/chlamydia-gonorrhea-and-syphilis. Accessed January 25, 2022.
- American Academy of Family Physicians. Clinical Preventive Service Recommendation: Syphilis. https://www.aafp.org/family-physician/patient-care/clinical-recommendations/all-clinical-recommendations/syphilis.html. Accessed September 20, 2020.
- American Academy of Family Physicians. Screening for Sexually Transmitted Infections Practice Manual. https://www.aafp.org/dam/AAFP/documents/patient_care/sti/hops19-sti-manual.pdf. Accessed January 25, 2022.
|Detection||The USPSTF found convincing evidence that screening test algorithms with high sensitivity and specificity are available to accurately detect syphilis infection.|
|Benefits of Early Detection and Intervention and Treatment||The USPSTF found convincing evidence that screening for syphilis and subsequent treatment of persons with syphilis with antibiotics can lead to substantial health benefits in nonpregnant persons who are at increased risk for syphilis infection by curing syphilis infection, preventing manifestations of late-stage disease, and preventing sexual transmission to others.|
|Harms of Early Detection and Intervention and Treatment||The USPSTF found limited evidence on the harms of screening for syphilis in nonpregnant persons who are at increased risk for infection. Potential harms of screening include false-positive results that require clinical evaluation, unnecessary anxiety to the patient, and the potential stigma of having a sexually transmitted infection. The harms of antibiotic treatment are well established, and the magnitude of these harms is no greater than small.|
|USPSTF Assessment||Using a reaffirmation process, the USPSTF concludes with high certainty that the net benefit of screening for syphilis infection in nonpregnant persons who are at increased risk for infection is substantial.|
Abbreviation: USPSTF = U.S. Preventive Services Task Force.