HIV/AIDS: Making the Connection

The interconnectedness of HIV/AIDS, other sexually transmitted diseases (STDs), tuberculosis (TB), and viral hepatitis grows increasingly apparent as biomedical and behavioral scientists learn more about people's susceptibility and risks. CDC is applying new research to the elimination of TB and the prevention of all major STDs, including HIV infection, and viral hepatitis.

HIV/AIDS and STDs
HIV/AIDS and TB
HIV/AIDS and Hepatitis C

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HIV/AIDS and STDs

Having an STD does not necessarily mean that the infected person also has HIV infection. However, continuing the risky behavior that led to STD infection may increase the likelihood of eventually becoming infected with HIV.

HIV infection and other STDs are linked not only by common behaviors, but also by biological mechanisms. Other STDs increase both HIV infectiousness and susceptibility. For example:

• Syphilis, genital herpes type 2, chancroid, and other infections that cause genital or rectal ulcers may increase the risk of HIV transmission per sexual exposure 10 to 50 times for male-to-female transmission and 50 to 300 times for female-to-male exposure.¹
• Nonulcerative STDs (e.g., chlamydia and gonorrhea) have been shown to increase the risk of HIV transmission by two-fold to five-fold.²
• Treatment of gonorrhea in HIV-infected men reduces the prevalence of HIV shedding in urethral secretions by approximately 50%.³

These relationships between HIV/AIDS and STDs illustrate why STD prevention is a key HIV prevention strategy. Integrating HIV and STD prevention efforts is vital to the success of both endeavors.⁴

Learn more about the role of STD prevention and treatment in HIV prevention:

• HIV Prevention Strategic Plan: Extended Through 2010
• CDC STD Treatment Guidelines 2006
• CDC Fact Sheet: The Role of STD Detection and Treatment in HIV Prevention (PDF)

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HIV/AIDS and TB

HIV weakens the immune system; TB thrives in a weakened immune system. Thus, each disease speeds the other's progress:

• Someone who is HIV-positive and infected with TB is many times more likely to become sick with TB than someone who is HIV-negative and infected with TB⁵
• TB is a leading cause of death among people who are HIV-positive.⁶

About one-third of the 33.2 million HIV-positive people worldwide are co-infected with TB⁷ and one in four people living with HIV die as a result of TB.⁸ In Africa, HIV is the single most important factor determining the increased incidence of TB in the past 10 years.⁹

Learn more about the role of HIV prevention and treatment in TB elimination:

• World Health Organization TB Fact Sheet
• Stop TB Partnership TB/HIV Working Group

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HIV/AIDS AND HEPATITIS C

The hepatitis C virus (HCV) is transmitted primarily by large or repeated direct exposures to contaminated blood via skin puncture. About one quarter of HIV-infected persons in the United States are also infected with hepatitis C virus (HCV). Coinfection rates vary by type of exposure:

• Coinfection with HIV and HCV is common among HIV-infected injection drug users (IDUs), between 50%-90%.¹⁰
• Coinfection is also common among persons with hemophilia who received clotting factor concentrates before 1987, when concentrates were treated to inactivate both viruses.¹¹
• The risk for acquiring infection through perinatal or sexual exposures is much lower for HCV than for HIV. For persons infected with HIV through sexual exposure (e.g., male-to-male sexual activity), coinfection with HCV is no more common than among similarly aged adults in the general population (3%-5%).¹²

HIV-HCV coinfection has been associated with higher titers of HCV, more rapid progression to HCV-related liver disease, and an increased risk for HCV-related cirrhosis of the liver. Because of this, HCV infection has been viewed as an opportunistic infection in HIV-infected persons. It is not considered an AIDS-defining illness. The effects of HCV coinfection on HIV disease progression are less certain. Since coinfected patients are living longer on highly active antiretroviral therapy (HAART), more data are needed to determine if HCV infection influences the long-term natural history of HIV infection.

Learn more about the role of HIV prevention and treatment in HCV prevention:

• CDC’s Fact Sheet on HIV and Viral Hepatitis
• CDC’s Frequently Asked Questions and Answers about Coinfection with HIV and Hepatitis C Virus (PDF), including treatment recommendations

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¹ HIV Prevention Strategic Plan Through 2005
² HIV Prevention Strategic Plan Through 2005
³ HIV Prevention Strategic Plan Through 2005
⁴ HIV Prevention Strategic Plan Through 2005
⁵ HIV Prevention Strategic Plan Through 2005
⁶ The Deadly Intersection Between TB and HIV, CDC
⁷ TB/HIV Facts 2009, World Health Organization
⁸ TB/HIV Facts 2009, World Health Organization
⁹ Fact Sheet on Tuberculosis, World Health Organization
¹⁰ Frequently Asked Questions and Answers about Coinfection with HIV and Hepatitis C, CDC (PDF)
¹¹ Frequently Asked Questions and Answers about Coinfection with HIV and Hepatitis C, CDC (PDF)
¹² Frequently Asked Questions and Answers about Coinfection with HIV and Hepatitis C, CDC (PDF)