HIV/AIDS Program

Over 333 million new cases of curable sexually transmitted diseases (STDs) and almost 6 million new cases of HIV occur in the world each year. In the US 40,000 new HIV infections and over 12 million new cases of STDs occur each year, with a majority of the new STD cases occurring in people under age 25.

The results of multiple studies clearly point to a causal relationship between the presence of other STDs and the transmission of HIV. HIV and other STDs are connected in at least four ways.

Similar behaviors put people at risk for both HIV and other STDs;
The presence of an STD can make people more susceptible to infection with HIV;
People co-infected with HIV and another STD can more easily transmit HIV infection to others; and
People with HIV and other STDs may have more frequent and serious symptoms related to those infections.

Common Risk Behaviors

Sexually transmitted diseases are transmitted through similar risk behaviors. Gonorrhea, chlamydia, herpes, and other classic sexually transmitted diseases are transmitted through unprotected vaginal, anal, and (less often) oral sex; these are the same sexual behaviors known to transmit HIV. Not unexpectedly, co-infection with HIV and other STDs is commonly noted in research. Condoms, used correctly and consistently, can help reduce the risk of acquiring STDs. However, condoms are not 100% effective and only protect the covered surfaces; thus they are less protective against some STDs, like genital warts and genital herpes.

STDs Increase Susceptibility to HIV Infection

Epidemiological studies confirm that persons are 2-5 times more likely to become infected with HIV when other STDs are present.

People with other STDs are more susceptible to HIV infection. STDs increase susceptibility in several ways. The STD may be associated with an ulcer or break on the mucosal or cutaneous surfaces of the genitals, allowing HIV easier entry to the bloodstream. For example, herpes, syphilis or chancroid lesions may serve as entryways for HIV. In addition, research indicates that genital infections attract CD4+ lymphocytes to the skin/mucosal surface. Genital infection, whether it be ulcerative (chanchroid, syphilis, genital herpes) or inflammatory, (gonorrhea, chlamydia, trichomoniasis) increases the number of white blood cells in the genital area and circulating in the blood. This increase in white blood cells increases the number of target cells that HIV can use to gain entry into the body.

STDs Increase The Transmission of HIV

HIV positive people co-infected with another STD can more efficiently transmit HIV to sexual partners. Shedding of HIV is known to occur more often and in higher concentrations from those with STDs than from those without STDs. For example, one study showed that HIV could frequently be found in high concentrations from herpes lesions in men infected with both HIV and herpes. Inflammatory STDs such as gonorrhea and chlamydia also increase the prevalence of HIV shedding and the HIV RNA copy numbers or "viral load" in genital secretions. ^{,, ,}For example, HIV-infected men with gonorrhea have a tenfold increase of shedding of HIV RNA in semen, but effective treatment of gonorrhea rapidly reduces HIV shedding to initial levels.¹² This increased shedding of HIV increases the amount of HIV present in the genital tract and thus makes HIV transmission to sexual partners more efficient.

HIV Predisposes People to More Serious STD Outbreaks

Due to immune system dysfunction, people with HIV infection often have more frequent and serious symptoms of other systemic STDs, particularly in the later stages of HIV infection when low CD4 cell counts indicate substantial damage to the immune system. For example, people with both HIV and herpes will often report more frequent and severe herpes outbreaks when their CD4 count is below 200. HIV has also been known to alter the clinical course of other infections such as syphilis, in the later stages of HIV infection when low CD4 cell counts occur.

STD Education and Treatment Can Reduce New HIV Infections.

Research clearly shows that prevention efforts that reduce STDs or risky behaviors associated with acquisition of STDs will also reduce new HIV infections.

Strong evidence demonstrating the relationship between improved STD management and a reduction in HIV comes from a study done in Tanzania. Communities that offered enhanced primary care of STDs experienced a 42% reduction in new HIV infections compared to control communities that received the standard management of STDs. The enhanced care provided antimicrobial drugs and more education about how to identify symptoms of STDs and where and how to seek treatment.

Evidence is accumulating that the practice of frequent douching is associated with an increasing risk for acquiring STDs.

Recommendations:

The following prevention interventions can be effective at reducing new infections of STDs and HIV:

A reduction in the number of new sexual partners.
Consistent and correct condom use with all new sexual partners.
The prompt diagnosis and treatment of all suspected STDs.
Education about the symptoms and consequences of common STDs.
Regular STD screening for those at risk for common STDs, with or without the presence of symptoms.
Easy access, for all, to STD care and treatment.
Education that douching (either vaginal or anal) may increase the risk of STDs and is not effective for the treatment of any STD.

Conclusions:

Recent research presents evidence for a causal link between STDs and HIV. People with STDs acquire HIV more easily and those with both an STD and HIV can more easily transmit HIV to sexual partners. Prevention and treatment of STDs can have a significant effect in reducing new HIV infections. For more information about HIV and other STDs call the HIV/AIDS Program at (206) 205-STDS (7837).

References:

Gerbase AC, Rowler JT and Mertens TE. Global epidemiology of sexually transmitted diseases. Lancet 1998;351(Suppl III):2-5.
World Health Organization. Report on the global HIV/AIDS epidemic. June 1998. (Available online at www.unaids.org.)
CDC. Trends in the HIV and AIDS Epidemic. CDC publication, 1998.
Institute of Medicine, Committee of Prevention and Control of Sexually Transmitted Diseases. The Hidden Epidemic: Confronting sexually transmitted diseases. National Academy Press, Washington DC, 1996.
Cohen MS. Sexually transmitted diseases enhance HIV transmission: no longer a hypothesis. Lancet 1998;351(Suppl III):5-7.
CDC. HIV Prevention Through Early Detection and treatment of Other Sexually Transmitted Diseases – United States. MMWR 1998:47(No. RR-12): page 2.
CDC. New Study helps explain how STDs may increase risk of HIV transmission: STDs damage cells that normally protect against infection. CDC News Release, July 2, 1998.
Schacker T, et al. Frequent recovery of HIV-1 from genial Herpes Simplex Virus lesions in HIV-1 infected men. JAMA 1998;280:61-66.
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Clemetson DBA, Moss GB, Willerfor DA, et al. Detection of HIV DNA in cervical and vaginal secretions. Prevalence and correlates among women in Nairobi, Kenya. JAMA 1993;269:2860-4.
Cohen MS, Hoffman IF, Royce RA, et al. Reduction of concentration of HIV-1 in semen after treatment of urethritis: implications for prevention of sexual transmission of HIV-1. Lancet 1997;349:1868-73.
Wasserheit JN. Epidemiological Synergy: Interrelationships between HIV infection and other sexually transmitted diseases. Sexually Transmitted Diseases, March-April 1992;19(2)61-77.
Institute of Medicine. The Hidden Epidemic: Confronting sexually transmitted diseases. National Academy Press, Washington DC, 1996, p 2-17.
Grosskurth H, Mosha F, Todd J, et al. Impact of improved treatment of sexually transmitted diseases on HIV infection in rural Tanzania: randomized controlled trial. Lancet 1995;346:530-36.
Zhang J, Thomas AG and Leybovich E. Vaginal douching and adverse health effects: a meta-analysis. American Journal of Public Health ,July 1997;87(7):1207-1211.