TB & HIV co-infection
TB and HIV co-infection is when people have both HIV infection, and also either latent or active TB disease. When someone has both HIV and TB each disease speeds up the progress of the other. In addition to HIV infection speeding up the progression from latent to active TB, TB bacteria also accelerate the progress of HIV infection.1Mayer, K & Hamilton, C. “Synergistic Pandemics: Confronting the Global HIV and Tuberculosis Epidemics" Clinical infectious diseases, 2010, 50 Suppl 3. S67-70. 10.1086/651475
HIV infection and infection with TB bacteria are though completely different infections. If you have HIV infection you will not get infected with TB bacteria unless you are in contact with someone who also is infected with TB bacteria. Although if you live in a country with a high prevalence of TB (such as India or South Africa) this may have happened without you realizing it. Similarly if you have TB you will not get infected with HIV unless you carry out an activity, such as unsafe sex, with someone who already has HIV infection.
TB also occurs earlier in the course of HIV infection than many other opportunistic infections. The risk of death in co-infected individuals is also twice that of HIV infected individuals without TB. This is even when antiretroviral (ARV) therapy is taken into account.2Suchindran, S. “Is HIV infection a Risk Factor for Multi-Drug Resistant Tuberculosis? A Systematic Review” PLoS one, May 2009, 4(5): e5561
The natural history of TB in people with HIV
When people have a damaged immune system, such as people with HIV who are not receiving antiretrovirals (ARVs), the natural history of TB is altered. Instead of there being a long latency phase between infection and development of disease, people with HIV can become ill with active TB disease within weeks to months, rather than the normal years to decades.
The risk of progressing from latent to active TB is estimated to be between 12 and 20 times greater in people living with HIV than among those without HIV infection.3Luetkemeyer, A. “Tuberculosis and HIV”, HIVInSite,
http://hivinsite.ucsf.edu/ This also means that they may become infectious and pass TB on to someone else, more quickly than would otherwise happen. Overall it is considered that the lifetime risk for HIV negative people of progressing from latent to active TB is about 5-10%. For HIV positive people this same figure is the annual risk.4“Implementing the WHO Stop TB Strategy: a handbook for national tuberculosis control programmes” Geneva, World Health Organization, 2008, p67 www.who.int/tb/publications/2008/
HIV positive people with pulmonary TB may have the classic symptoms of TB, but many people with both TB and HIV infection have few symptoms of TB or even less specific ones. In addition, up to a fifth of people with both pulmonary TB and HIV have normal chest X-rays. HIV positive people with TB may indeed frequently have so called “sub clinical” TB. This is often not recognized as TB and subsequently there can be delays in both TB diagnosis and TB treatment.
People living with HIV are more likely to have extrapulmonary TB. Therefore it is much more common in countries with a high HIV prevalence, such as South Africa.5"Extrapulmonary TB", TBCAB, http://www.tbonline.info/posts/2016/3/31/extrapulmonary-tb/
Global TB/HIV co-infection statistics
In 2016 374,000 people who had both TB and HIV are estimated to have died. This is in addition to the 1.3 million people who died from TB alone.6“Global Tuberculosis Control 2017”, WHO, Geneva, 2017,
www.who.int/tb/publications/global_report/en/ Those people who have HIV and TB co-infection when they die, are internationally reported as having died of HIV infection.7“International Classification of Diseases (ICD)”, WHO, Geneva, 2010
www.who.int/classifications/icd/en/ In total an estimated 1.2 million people died of HIV infection in 2014. So:
Deaths from HIV and TB co-infection: 374,000
Deaths from TB alone: 1,300,000
Deaths from HIV alone: 826,000
So more people now die from TB than from HIV related infections.
Also in 2016 there were an estimated 10.4 million new cases of active TB worldwide. Globally 10% of the incident TB cases in 2016 are estimated to have been among people living with HIV.
|Region||Total TB Mortality||0 - 14 years TB Mortality||Male >15 years||Female >15 years||Population|
If there is a "plus sign" click on it for more columns
The WHO African Region accounted for 86% of these deaths, with the M:F ratio being 1.8. The M:F ratio in other regions varied from 1.3 in the WHO Eastern Mediterranean Region to 2.4 in the WHO European Region.
Globally in 2015 55% of notified TB patients had a documented HIV test result. This is an 18 fold increase in testing coverage since 2004. In the African region where the burden of HIV associated TB is highest 81% of TB patients had a documented HIV test result.
Diagnosing TB and HIV in TB and HIV co-infection
Because of the limitations of current TB tests, it is even more difficult to diagnose TB in HIV positive individuals, than to diagnose TB in people without HIV infection. Many people with HIV will have a false negative result from a TB sputum smear test. This can result in a large number of cases of active TB disease going undiagnosed.
By contrast the diagnosis of HIV in people with TB should always be straightforward because of the availability of quick and cheap point of care diagnostics for HIV infection. The Stop TB Partnership’s Global Plan to Stop TB had as a target, that by 2015, all patients with TB should be tested for HIV.8“The Global Plan to Stop TB”, WHO, Geneva, 2011, 12 www.stoptb.org/global/plan/
Treating TB & HIV co-infection
The proportion of known HIV positive TB patients on antiretroviral therapy (ARVs) is 78% globally, and above 90% in India, Kenya, Malawi, Mozambique, Namibia and Swaziland.
Starting treatment for either HIV or TB
The decision to start treatment for either HIV or TB when there is co-infection, should take into account a number of factors including:
- Has the person got symptoms of, and is ill with either TB, or some other HIV related opportunistic infection?
- Is the person already having treatment for either TB or HIV infection?
- What drugs are available for the treatment of HIV infection, and indeed TB, if the person is not already receiving treatment?
- If there is a need for both HIV and TB treatment, are there experienced health care workers and/or guidelines available to provide the necessary expertise on this?
Providing HIV ARV therapy and anti TB drug treatment together
The provision of HIV ARV therapy and anti TB drug treatment at the same time involves a number of potential difficulties including:9Piggott, D. “Timing of Antiretroviral Therapy for HIV in the Setting of TB Treatment” Clin Dev Immunol., 2011, 103917 www.hindawi.com/journals/cdi/”
- Cumulative drug toxicities
- Drug - drug interactions
- A high pill burden
- The Immune Reconstitution Inflammatory Syndrome (IRIS)
Starting both HIV ARV and anti TB drug therapy
For adults with both TB and HIV infection, who need to receive both antiretrovirals and TB drugs, the WHO guidelines recommend starting HIV ARVs between 2 and 8 weeks after starting TB treatment for those individuals who have a CD4 count of less than 200mm3. For people with both TB and HIV it is not now considered necessary to delay the initiation of ARV therapy until TB treatment has been completed.10“Antiretroviral Therapy for HIV Infection in Adults and Adolescents: Recommendations for a public health approach 2010 revision”, WHO, Geneva, 2010, 45 www.who.int/hiv/topics/treatment/en/index.html
The Stop TB Partnership’s Global Plan to Stop TB had as a target, that by 2015, all HIV positive TB patients should be receiving ARV treatment.11“The Global Plan to Stop TB”, WHO, Geneva, 2011, 12 www.stoptb.org/global/plan/ But actually by 2013 it was estimated that only 70% of notified TB patients co-infected with HIV were receiving ARVs.12“Global Tuberculosis Control 2014”, WHO, Geneva, 2014,
The stigmas of TB and HIV/AIDS
The stigmas of HIV and TB have come full circle.
In the early days of the HIV/AIDS epidemic, people were said to have died of TB when they had actually died of AIDS.13Eddie Vulani Maluleke in Nobody Ever Said AIDS:Stories & Poems from Southern Africa, Rasebotsa et al, 2004
- We all died
- Coughed and died
- We died of TB
- That was us
- Whispering it at funerals
- Because nobody ever said AIDS
Now in the townships of South Africa, people will enter the shack (township home) of someone with HIV, but they will stop at the door if the person has XDR TB. 14Personal communication There is more about TB in South Africa and HIV in South Africa.