According to CDC figures,(www.cdc.gov) the rate of primary and secondary syphilis in the United States has increased since 2000, which saw the lowest rate of infection since reporting began 1941. In 2013, 17,375 cases -- or 5.5 cases per 100,000 people -- were reported.
It's a public health issue that has long commanded national attention, and on Dec. 15, the U.S. Preventive Services Task Force (USPSTF) released an updated draft statement(www.uspreventiveservicestaskforce.org) and draft evidence review(www.uspreventiveservicestaskforce.org) recommending that nonpregnant adults and adolescents who are at increased risk for syphilis be screened for the disease -- an "A" recommendation.(www.uspreventiveservicestaskforce.org)
The USPSTF said patients at highest risk for syphilis include men who have sex with men (MSM) and people with HIV infection. Based on 2013 surveillance data, 75 percent of cases of primary and secondary syphilis occurred among MSM, and almost half of MSM who were diagnosed as having syphilis also were infected with HIV.
One study found rates of syphilis coinfection were five times higher in HIV-positive MSM compared with HIV-positive men who didn't have sex with men.
- On Dec. 15, the U.S. Preventive Services Task Force (USPSTF) released a draft recommendation statement saying nonpregnant adults and adolescents at increased risk for syphilis should be screened for the infection.
- The recommendation statement lays out specifics regarding behavioral, sociodemographic and other characteristics that boost infection risk.
- This recommendation complements a 2009 USPSTF recommendation to screen all pregnant women for syphilis infection, which the AAFP mirrored at the time.
This recommendation complements a 2009 USPSTF recommendation statement(www.uspreventiveservicestaskforce.org) to screen for syphilis infection in all pregnant women, which the AAFP's recommendation for this population group mirrored.
"Fortunately, in the case of syphilis, there are accurate tests available for screening and effective therapies that can cure syphilis, prevent further complications and prevent the spread of infection," said USPSTF member Ann Kurth, Ph.D., R.N., M.S.N., M.P.H., in a news release.(www.uspreventiveservicestaskforce.org)
The USPSTF release also noted that the risk for syphilis can be reduced by consistently using latex condoms, limiting sexual activity to a single partner in a mutually monogamous relationship or by abstaining from sex.
Additional Risk Factors
The task force recommended that when deciding who to screen for syphilis infection, physicians should also consider other sociodemographic factors that are associated with increased infection rates, including male gender combined with age younger than 29, race/ethnicity, geographical location, incarceration and working in the sex industry.
Men accounted for 91 percent of all cases of primary and secondary syphilis in 2013, with those ages 20-29 having the highest disease prevalence -- nearly three times higher than that of the U.S. male population overall.
Syphilis prevalence rates also are higher among specific racial/ethnic groups. In 2013, for example, rates of primary and secondary syphilis were highest among blacks (16.8 cases per 100,000), followed by native Hawaiians/Pacific Islanders (8.6 cases per 100,000), Hispanics (6.3 cases per 100,000), American Indians/Alaska natives (4.6 cases per 100,000), whites (3 cases per 100,000) and Asians (2.5 cases per 100,000).
It's important for physicians to be aware of the prevalence of syphilis in their communities. For example, the Southern United States accounts for 40 percent of syphilis cases, but the case rate is currently highest in the Western United States (6.8 cases per 100,000 persons). In addition, metropolitan areas experience increased prevalence rates of syphilis.
Accuracy of Screening Tests
Screening for syphilis usually requires a two-step process, with a nontreponemal test such as a rapid plasma reagin (RPR) or Venereal Disease Research Laboratory (VDRL) test performed first, followed by a confirmatory treponemal antibody detection test such as a Treponema pallidum particle agglutination (TP-PA) or fluorescent treponemal antibody absorption (FTA-ABS) test if initial test results are positive. Positive results on both tests indicate past or present syphilis infection.
Sensitivity of the RPR and VDRL tests is estimated to be 78 percent to 86 percent for detecting primary syphilis infection, 100 percent for detecting secondary syphilis infection, and 96 percent to 98 percent for detecting latent syphilis infection. Specificity is about 98 percent for each test but may be reduced in people who have pre-existing conditions (i.e., collagen vascular disease, pregnancy, IV drug use, advanced malignancy, tuberculosis, malaria, and viral or rickettsial disease) that produce false-positive results.
The TP-PA and FTA-ABS tests have a sensitivity of 84 percent to 88 percent for detecting primary syphilis infection and almost 100 percent for detecting syphilis infection in other stages, as well as a specificity of 96 percent to 97 percent.
The current draft recommendation to screen those at increased risk is consistent with and updates the 2004 USPSTF recommendation for this patient population. The AAFP issued an identical recommendation at that time.
"Fifteen years ago, syphilis was an uncommon diagnosis in this country," Jennifer Frost, M.D., medical director for the AAFP Health of the Public and Science Division, told AAFP News. "The rate has more than doubled since them, particularly in gay and bisexual men. And although the USPSTF's recommendation mirrors its 2004 recommendation, we need to have heightened awareness about whether our patients are at risk so that they can be informed about the importance of prevention, screened and treated if their tests are positive."
The USPSTF will accept comments on the draft recommendation statement(www.uspreventiveservicestaskforce.org) and on its accompanying draft evidence review(www.uspreventiveservicestaskforce.org) through Jan. 18.
The AAFP is reviewing the USPSTF's draft recommendation and will update its own recommendation after the task force publishes its final recommendation statement.
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Uptick in Congenital Syphilis Causes Concern
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