March 12, 2008
Chicago -- The U.S. syphilis rate increased for the seventh consecutive year in 2007, largely reflecting continued increases among men who have sex with men (MSM), according to preliminary data from the Centers for Disease Control and Prevention (CDC) presented today at the 2008 National STD Prevention Conference.
Other studies released at the conference indicate that many MSM with sexually transmitted diseases (STDs) remain undiagnosed due to inadequate STD testing.
"STDs remain a major threat to the health of gay and bisexual men, in part because having an STD other than HIV can increase the risk of transmitting or acquiring HIV," said Kevin Fenton, M.D., director of CDCs National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention. "The resurgence of syphilis among MSM represents a formidable challenge to our STD prevention efforts, but one that is surmountable. The solution comes down to making STD screening and treatment a central part of medical care for gay and bisexual men, while finding innovative ways to help MSM avoid STD infections -- including HIV -- in the first place."
The preliminary 2007 syphilis data show that the national rate of primary and secondary syphilis -- the most infectious stages of the disease -- increased 16 percent between 2006 and 2007, from 3.2 to 3.7 cases per 100,000 population. As in recent years, this overall increase was driven by continued increases among males (from 5.7 per 100,000 in 2006 to 6.4 per 100,000 in 2007).
Several sources of data indicate that substantial increases in syphilis among MSM since 2000 largely account for the overall trend in males.
The rate among females also increased between 2006 and 2007, from 1.0 to 1.1 cases per 100,000 population. While the reasons for the third consecutive annual increase among females are still being examined, this emerging trend deepens concerns about a potential resurgence of syphilis among women, after more than a decade of declining rates.
Rates among African-Americans also remain much higher than rates among whites -- seven times higher for African-American men and 14 times higher for African-American women. Reported syphilis rates among African-American men increased 25 percent from 2006 and 2007 (17.1 to 21.5 cases per 100,000 population). The rate among African-American women rose 12 percent from 2006 and 2007 (4.8 to 5.4 cases per 100,000 population).
Since 2002, CDC has recommended that sexually active MSM be tested at least annually for syphilis, chlamydia and gonorrhea -- at all anatomic sites of reported STD exposure (oral, anal and/or urethral). CDC also recommends at least annual STD testing for all individuals with HIV infection. However, three new studies indicate the urgent need to continue increasing STD screening rates among MSM.
The first, an eight-city STD clinic study led by CDCs Kristen Mahle, found that as many as one-third of gonorrhea infections among MSM who were not HIV-infected were missed because MSM were not tested at all relevant anatomical sites. MSM were tested at all three sites only about half (52 percent) of the time. In another study, led by CDC researcher Eric Tai, only 49 percent of MSM surveyed in 15 cities in 2003-2005 reported being tested for syphilis, 35 percent reported being tested for gonorrhea and only 32 percent were screened for chlamydia in the past year. The third study, led by CDCs Karen Hoover, found that 82 percent of HIV-infected MSM in eight cities were tested for syphilis in the past year, but only 22 percent or fewer were tested for gonorrhea or chlamydia.
Another study, led by Julius Schachter of the University of California, San Francisco, could help pave the way for more thorough STD screening among MSM. The researchers found that a DNA testing method called a nucleic acid amplification test which is already widely used to screen for genital gonorrhea and chlamydia infections, was able to detect at least twice as many gonorrhea and chlamydia infections in the throat and rectum as a traditional bacterial culture test, which is the current standard of diagnosing infections at extra-genital sites.
"While STD screening is by no means the only weapon in our STD prevention arsenal, it is certainly one of our best tools for ensuring prompt diagnosis and treatment and slowing the transmission of these diseases," said John M. Douglas, Jr., M.D., director of CDCs Division of STD Prevention. "We are committed to supporting the efforts of physicians in the community as they work to increase screening among their patients. At the same time, were working to support broader STD prevention programs for MSM, women, African-Americans and others who remain at risk."
In light of recent challenges in syphilis prevention, CDC has been working with public health, medical and community partners since 2006 to implement an updated National Plan to Eliminate Syphilis. These efforts are designed to sustain progress made since the early 1990s in populations traditionally at risk, including African-Americans and women of all races, and to support innovative solutions to fight the resurgence of syphilis among MSM. Recent examples of new strategies include:
At the conference, one new modeling study underscores the potential for syphilis elimination funding to have an impact on disease rates. Led by CDCs Harrell Chesson, researchers examined the correlation between state-level syphilis rates and federal syphilis elimination funding from 1999-2005 in the 28 states that were first provided with the funding, beginning in 1998. The researchers found that, in aggregate, these 28 states had either larger decreases or smaller increases in syphilis rates throughout the period than did other states, which either received syphilis elimination funding in later years or not at all.