HIV/TB co-infections poses health battle on two fronts
Every year, tuberculosis (TB) kills about 1.7 million people and 9 million develop active disease. TB is on the rise in countries with high HIV rates, particularly in southern Africa, which has the highest rates of HIV. Tuberculosis is one of the leading causes of death for people living with HIV/AIDS, and in the past 15 years, new TB cases have tripled in countries with high HIV prevalence. People living with HIV/AIDS are up to 50 times more likely to develop active TB in a given year compared with HIV-negative individuals, and roughly a third of the 33 million people living with HIV/AIDS worldwide are infected with latent TB. Yet, in 2006 less than one percent of people living with HIV/AIDS were screened for TB.
While the treatment of HIV has received substantial global attention, people living with both HIV and TB have slipped mostly under the radar mainly because sensitive diagnostic tools are lacking and treatment for co-infected patients is complicated. While programs still focus on individual diseases, patients may have both and other diseases.
Diagnosis of TB in HIV-positive individuals is difficult, often leading to delays in treatment, which in turn contribute to increased death rates. A standard test - the microscopy of the sputum - was invented more than a century ago, and cannot detect TB, in the majority of people who are HIV-positive. Rapid culture tests - in which sputum samples are put on a plate or broth and grown - detect more patients but are very complex to perform. Culture tests, due to their complexity, are far from a reality in the places where most patients live, impeding far too many patients from receiving adequate and timely treatment.
Treatment for TB is outdated and complicated in itself and not adapted to the specific problems of co-infected patients. Health-care providers have to use at least four TB drugs initially. Sometimes these drugs have side effects, including nausea, vomiting, neuropathy, hepatitis, and others. If the drugs do not cause side effects, then clinicians must ensure that they are not negatively impacting the effects of the HIV medications the patient is also taking. No new TB drugs have been developed for global or large-scale use in decades and the increase in drug resistant cases of TB adds another dimension of complexity.
Perhaps most importantly, global donors as well as national governments must invest in new diagnostics and treatments to really begin to face this growing health threat. MSF is calling for a massive scale up in research and development of TB medicines and diagnostic tools, and vaccines. Around $2 billion needs to be invested annually in the development of new tools for TB, but only an estimated $429 million was invested in 2006, according to the Treatment Action Group.
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