HIV-STD synergy worries public health officials

Drugs, Viagra play role in problem

There is little good news about sexually transmitted diseases (STDs) and sexual risk-taking behavior in the United States, and this continues to worry public health officials and HIV researchers.

Syphilis infection rates continue to increase in the United States for the third straight year, particularly among men who have sex with men (MSM). Other data show STD rates are high especially among MSM who use illegal drugs, such as crystal methamphetamine, and are even higher among MSM who combine crystal meth with sildenafil citrate (Viagra).1,2

Cases of primary and secondary syphilis increased about 3% between 2002 and 2003, according to data from the Centers for Disease Control and Prevention (CDC).

Between 2000 and 2003, reported syphilis cases have increased 18%, and the overall syphilis rate has increased from 2.1 cases per 100,000 people in 2000 to 2.5 cases per 100,000 people in 2003, the CDC reports.

The increase is entirely among men, who have had a 65% increase in syphilis cases in the past three years; whereas, cases of syphilis among women have declined 50% in the same period, according to CDC data.

Likewise, STD rates continue to climb among people already infected with HIV.

"Studies are asking HIV-infected people about sexual behaviors, and it turns out that news isn’t good — they haven’t gotten the message yet that responsibility is important," says Myron Cohen, MD, a J. Herbert Bates distinguished professor of medicine, microbiology, and immunology and director of the Division of Infectious Diseases and the UNC Center for Infectious Diseases at the University of North Carolina at Chapel Hill.

"Some studies are collecting samples from HIV-positive people, and when they have new STDs, that’s of great concern," he says.

Some of the CDC’s recent findings include the following:

  • HIV-positive MSM are twice as likely to have gonorrhea as HIV-negative MSM.3
  • MSM at a San Francisco STD clinic who used crystal meth were 2.2 times more likely to be HIV-positive, 4.9 times more likely to have syphilis, and 1.7 times more likely to have gonorrhea.1
  • MSM who use crystal or sildenafil citrate are more likely to engage in unprotected sex, and men who used sildenafil citrate were 6.5 times more likely to engage in unprotected insertive anal intercourse.2

"A study conducted by myself and colleagues at the CDC and San Francisco Department of Public Health assesses the direct link of substance use and sexual risk behavior of MSM during the most recent anal sexual encounters," says Gordon Mansergh, PhD, a CDC behavioral scientist who spoke at the 2004 National STD Prevention Conference in Philadelphia in March.

"Men who used crystal during the sexual encounter were twice as likely to report unreported receptive anal sex," he explains. "The links between sildenafil citrate and insertive sex and crystal and receptive sex were independent of each other and other substance use."

Moreover, the findings were even stronger for risk behavior with a partner of different or unknown HIV serostatus than the person who responded to the survey, Mansergh adds.

"The most striking finding was that men who use crystal and sildenafil citrate together were 6.1 times as likely to have syphilis as those who didn’t use either drug," he says. "Two other studies provided evidence that the Internet and other sex venues play a role in syphilis rates among MSM."

Research consistently has shown a link between HIV infection, sexual risk behaviors, and other STD infections, Cohen says.

"One theme that has been pursued extremely aggressively is that STDs amplify HIV transmission, and it’s not surprising because HIV is another STD and STDs travel in neighborhoods together," he explains.

The big research debate involves the hierarchy of risk among STD infections and where to focus the most public health attention, Cohen says.

For instance, herpes simplex virus (HSV) is a very common STD infection and so a great deal of public health energy has gone into this area, including looking at the incidence of HIV/HSV co-transmission, he points out. "When people shed HSV-2, they put themselves at that moment in time at greater risk for acquiring HIV or transmitting HIV. STDs are bad actors in the HIV epidemic."

Declining rates for HSV-2 infections

The most positive news to come out of the 2004 National STD Prevention Conference was that the prevalence of HSV-2 infection declined significantly between the periods of 1994-1998 and 1999-2000, dropping from 21.3% infected with the virus to 17.2%, a 17% overall decline, according to CDC data.

Designing HIV prevention messages for MSM who also are at greater risk for STDs remains a CDC priority, says Ronald O. Valdiserri, MD, MPH, deputy director of the National Center for HIV/STD Treatment and Prevention at the CDC. Valdiserri spoke at the 2004 National STD Prevention Conference.

"The high rates of HIV infection among men with STDs emphasizes the urgent need to tailor HIV-prevention efforts for HIV-infected gay and bisexual men," he says. "People living with HIV need a lifetime of support to maintain safe behaviors and to protect their health and their partners’ health."

In some STD clinics, the increases are particularly striking.

For instance, at Fenway Community Health in Boston, syphilis cases have risen from its nadir of two cases in 1997 to 51 cases in 2003, explains Kenneth Mayer, MD, medical research director at Fenway. Mayer also spoke at the national STD conference.

Likewise, gonorrhea diagnoses increased 139% between 1997 and 2002, from 41 cases to 98 cases, he says.

"This is without any other reason than the increase in risk behavior," Mayer adds. "About 15% of the 7,500 cohort of the men who receive services at Fenway are HIV-infected, and when we do an analysis of risk factors for having an incident case of syphilis, HIV-positive serostatus was the strongest single predictor."

One of the chief challenges facing clinicians and public health officials involves treating and providing prevention services to at-risk people in a respectful environment, Cohen says.

"We have to better understand how to create an environment in which people get proper treatment and respect without stigma," he explains. "This is something we have not done."

Mayer points out that while STDs and HIV are preventable diseases that are not easy to get unless one engages in risk behavior, the solution is far from simple.

"Behavior change is complicated and takes time," he says. "The realities about HIV have changed — it’s perceived now as being a more manageable disease than it was 20 years ago, and different public health strategies are needed."

Unfortunately, all of this costs money, and the current government environment does not include a substantial investment in public health at the federal level, Mayer says.

"So as someone who is not a federal employee or told to say this, as a member of the public health community, I say this is the time to put in more money — not just because these are entitlements or a God-given right, but because it’s in the overall interest of America’s public health.

"We’re not hermetically sealed, so increased rates of syphilis among gay men affect other people’s lives, and this should be enough of a reason for the public to be concerned," he adds.

References

1. Mitchell S J. Methamphetamine use, sexual behavior, and sexually transmitted diseases among men who have sex with men seen in an STD clinic, San Francisco 2002-2003. Presented at the 2004 National STD Prevention Conference. Philadelphia; March 2004. Abstract 1357.

2. Mansergh G. Crystal use, Viagra use, and specific sexual risk behaviors of men who have sex with men during a recent anal sex encounter. Presented at the 2004 National STD Prevention Conference. Philadelphia; March 2004. Abstract 1034.

3. McLean C. Gonorrhea positivity among men who have sex with men attending STD clinics in the United States, 2002. Presented at the 2004 National STD Prevention Conference. Philadelphia; March 2004. Abstract 1128.