Based on a review of the evidence, the task force recommends screening for syphilis infection in people who are at increased risk for infection. This is an “A” statement, and applies to asymptomatic nonpregnant adolescents and adults who have ever been sexually active and are at increased risk for infection. The USPSTF has addressed screening for syphilis in pregnant women in a separate recommendation.
“Screening people who are at increased risk can identify the infection so it can be treated before problems develop,” said Katrina Donahue, M.D., M.P.H., a professor and vice chair of research in the Department of Family Medicine at the University of North Carolina, Chapel Hill, and a member of the task force, in a USPSTF bulletin. “Clinicians play an important role in helping to lower the rising rates of syphilis infection and keeping at-risk patients healthy.”
After reaching historic lows in 2000 and 2001, rates of primary and secondary syphilis have increased almost every year since; according to the CDC, more than 129,000 cases of syphilis were reported in the United States in 2019, the last year for which data are available. Other CDC data suggest there are racial and ethnic health disparities related to syphilis, as the rates of reported cases among Black adolescents and adults, American Indian/Alaska Native populations and Hispanic individuals are considerably higher than in white individuals.
The draft recommendation statement reaffirms the task force’s 2016 recommendation statement on the topic. In the 2016 recommendation, the USPSTF also recommended (at an “A” grade) screening for syphilis infection in individuals who were at increased risk for infection.
The AAFP supported the 2016 recommendation.
In the draft recommendation statement, the task force noted that it chose to use a reaffirmation deliberation process to update the recommendation. The USPSTF uses this process for well-established, evidence-based standards of practice in current primary care for which only a very high level of evidence would justify a change in the recommendation’s grade.
In deliberating the evidence, the task force considers whether the new evidence is of sufficient strength and quality to change its previous conclusions about the evidence. Because the USPSTF found no new substantial evidence to change its recommendation, it reaffirmed the recommendation to screen for syphilis in nonpregnant adolescents and adults.
To reaffirm its recommendation, the USPSTF commissioned a reaffirmation evidence update that focused on the performance of risk assessment tools and the benefits and harms of screening. The task force did not include a review of treatments, as it has previously determined that treatment for these infections are effective and well-established.
The evidence update consisted of a literature search of studies published on Medline and the Cochrane Central Register of Controlled Trials between Jan. 1, 2016, and Oct. 28, 2020. The task force also performed a more limited literature search that compared testing algorithms and the accuracy of rapid point-of-care tests. A total of three studies reported in five publications were included in the update.
The task force reviewed one fair-quality study that examined trends in syphilis testing and detection among sexually active men who have sex with men. The study found that screening in this population was associated with increases in the detection of early asymptomatic syphilis and decreases in secondary syphilis, which suggested that screening is likely to interrupt syphilis progression. No studies reported on the effectiveness of screening on acquisition or transmission of other sexually transmitted infections or other complications.
With regard to harms, the task force also reviewed one fair-quality pre-post study that examined emotional stress associated with rapid point-of-care STI testing. The results suggested that emotional stress may be a common experience for individuals both before and after testing, and that factors associated with increased stress included history of injected drug use, Black race, less than a high school education and single marital status.
In addition, the task force summarized the pros and cons of two types of sequencing algorithms used to detect primary and late latent syphilis: traditional (which utilizes a nontreponemal test as the initial screen, with reactive samples confirmed via a treponemal test) and reverse (which uses a treponemal test as the initial screen, followed by a nontreponemal test for confirmation). The study concluded that the traditional algorithm may be more appropriate for smaller laboratories that have lower volumes of testing because performing manual nontreponemal screening assays would not significantly affect workflow. Conversely, the reverse algorithm may be more suitable for larger laboratories where automated testing processes can improve workflow and efficiency, or for smaller labs that serve higher-risk populations, where patients may be at greater risk for primary and latent syphilis that is more likely to be missed by the traditional algorithm.
Finally, the task force reviewed a 2020 systematic review on the performance of the Syphilis Health Check, a rapid point-of-care test, in laboratory and real-world settings. Pooled sensitivity from the laboratory evaluations was 98.5%, while pooled specificity was 95.9%. The pooled sensitivity for prospective studies was 87.7%, and the pooled specificity was 96.7%. However, in two prospective studies the sensitivity was only 50%, an inconsistency that could have been accounted for due to differences in protocols, training and specimen collection. The task force concluded that overall, the Syphilis Health Check had “reasonable test performance,” but also suggested additional studies be conducted to investigate factors that contributed to lower sensitivity in real-world practice.
Along with more research on point-of-care tests, the task force called for more studies that would be more generalizable to the U.S. population, as well as studies on novel testing approaches, ways to identify individuals most likely to benefit from screening, and the effectiveness of specific screening intervals among different risk populations.
When determining who should be screened, the USPSTF bulletin also stated that clinicians consider the prevalence of syphilis infection in their particular communities and assess their patients’ individual risks. The bulletin further stated that anyone who is sexually active should discuss their risk factors for syphilis and other STIs with a clinician.
“The task force is calling for screening all adolescents and adults who are at increased risk for syphilis, so determining risk level is an important part of this recommendation,” said Michael Barry, M.D., the task force’s vice chair. “Clinicians should be aware of how common syphilis infections are in the communities they serve and their patient’s individual risk factors, including sexual history.”
All comments will be considered as the task force prepares its final recommendation statement.