The Link Between STDs and HIV

How HIV and Sexually Transmitted Diseases are Related

With the attention the HIV epidemic gets in the media, the alarming rates of infection with sexually transmitted diseases (STDs) like syphilis and gonorrhea are often overlooked. Few people realize that there is a connection between STD infection rates and HIV infection rates. And most people don't realize that by treating STDs, they can decrease the risk of HIV infection. Obviously there is a distinct connection between the two conditions. Let's look at this connection between HIV and STDs.

The Link Between HIV and STDs

It's been well documented since the early 1990s that people who are infected with an STD such as gonorrhea, syphilis, or herpes are much more likely to acquire an HIV infection. If an HIV-infected person has an STD as well, their risk of infecting another person goes up dramatically. But why? What does one have to do with the other? Experts site a couple of reasons for this connection:

• Increased susceptibility - Intact skin is an excellent barrier against HIV. STDs such as syphilis and herpes that are characterized by lesions or ulcers on the genitals interrupt that barrier, creating a site for HIV to enter the blood and infect the individual. In addition, STDs like chlamydia that don't cause ulcers do stimulate the white blood cells of the immune system to concentrate in the genital area to help fight the STD. This increased concentration of white blood cells means there are more CD4 cells for HIV to infect. In other words, STDs such as chlamydia increase the number of cells that are vulnerable to HIV and therefore increase the risk of HIV infection.

• More Infectious - For reasons that are not quite clear, HIV-infected people who are also infected with STDs have higher concentrations of HIV in their genital fluids. For instance, men who have HIV and gonorrhea are found to have significantly more HIV in their semen than HIV-infected men who are not also infected with gonorrhea. Obviously, if there is more HIV in genital fluids, the chance of infecting their partner rises simply because the higher concentrations of HIV means the chance of HIV entering the negative partner during sex goes up.

Treat the STD, and HIV Risk Goes Down

Studies of women with ulcerative STD lesions found higher levels of HIV present in their genital fluid. After treatment, the amount of HIV in the genital fluid decreased to levels similar to women without ulcerative STDs. Another important phenomenon is that treating STDs not only decreases the HIV risk in the individual but it also decreases infection rates in entire communities. Why is that so?

• Decreased Ability to Transmit HIV - STD treatment not only treats the sexually transmitted disease but also decreases the amount of HIV in their genital secretions meaning there is less HIV available to infect a partner.

• Decrease HIV Spread Within Communities - Under certain circumstances, STD treatment can reduce HIV infection rates within entire communities. But under what conditions?
  • adequate access to STD treatments within the community
  • communities where the STD rate is high and the heterosexual population is young
  • communities where there is an emphasis and importance placed upon STD treatment

When these conditions exist within a specific community or population, STD treatment decreases the HIV infection rate.

Keep in mind that these trends are really most significant at the population level. At the individual level, decrease in HIV transmission is relatively small. But when you are talking about a population of 20 million, a small reduction in HIV transmission translates into a lot of negative HIV tests. But in no way should STD treatment be considered a substitute for safer sex practices, most notably condoms.

How Do We Take Advantage of the Link Between STDs and HIV

We've learned that STD treatment can help decrease HIV infection rates. So it would be logical to use that fact when planning HIV prevention programs and education. Comprehensive STD prevention, education and treatment programs can play a vital role in decreasing the sexual transmission of HIV. Also, monitoring new STD infection rates can give HIV prevention specialists an idea of which populations are primed for an increase in HIV infection rates. Finally, by combining HIV and STD prevention efforts, resources will be used in a more efficient manner and both epidemics will be better controlled.

What Needs to Be Done

• STD prevention and treatment programs should become major components of all HIV prevention programs.

• In areas particularly hard hit by HIV, STD screening and treatment programs should be expanded and assigned a high priority.

More Information About The STD-HIV Link

• What Do the Studies Show?

• 10 Tips to Help Reduce Your Risk of STDs

• Condom Use is the Key to Prevention

• STD Resources

_Sources

1. Fleming DT, Wasserheit JN. 1999. From epidemiological synergy to public health policy and practice: The contribution of other sexually transmitted diseases to sexual transmission of HIV infection. Sexually Transmitted Infections 75:3-17.

2. Grosskurth H, Mosha F, Todd J, et al. 1995. Impact of improved treatment of sexually transmitted diseases on HIV infection in rural Tanzania: Randomized controlled trial. Lancet 346:630-6.

3. Wasserheit JN. 1992. Epidemiologic synergy: Interrelationships between human immunodeficiency virus infection and other sexually transmitted diseases. Sexually Transmitted Diseases 9:61-77.

4. Wawer MJ, Sewankambo NK, Serwadda D., et al. 1999. Control of sexually transmitted diseases for AIDS prevention in Uganda: a randomized community trial. Rakai Project Study Group. Lancet. 353(9152):525-35.