Quarter of deaths in people with HIV caused by TB, WHO reports

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Around one-quarter of deaths in people with HIV worldwide were caused by TB in 2007, the World Health Organization said today. Around 450,000 people with HIV died of TB in 2007, WHO estimates, and there were 1.4 million HIV-positive TB cases.

HIV-positive people are around 20 times more likely to develop TB than HIV-negative people in countries with a high HIV prevalence.

The figures were released today in WHO’s 2009 Global tuberculosis control report, and represent a substantial upward revision of previous estimates.

Glossary

isoniazid

An antibiotic that works by stopping the growth of bacteria. It is used with other medications to treat active tuberculosis (TB) infections, and on its own to prevent active TB in people who may be infected with the bacteria without showing any symptoms (latent TB). 

infection control

Infection prevention and control (IPC) aims to prevent or stop the spread of infections in healthcare settings. Standard precautions include hand hygiene, using personal protective equipment, safe handling and disposal of sharp objects (relevant for HIV and other blood-borne viruses), safe handling and disposal of waste, and spillage management.

cure

To eliminate a disease or a condition in an individual, or to fully restore health. A cure for HIV infection is one of the ultimate long-term goals of research today. It refers to a strategy or strategies that would eliminate HIV from a person’s body, or permanently control the virus and render it unable to cause disease. A ‘sterilising’ cure would completely eliminate the virus. A ‘functional’ cure would suppress HIV viral load, keeping it below the level of detection without the use of ART. The virus would not be eliminated from the body but would be effectively controlled and prevented from causing any illness. 

The high burden of deaths in people with HIV due to TB is especially alarming because TB is preventable. Early diagnosis and treatment now results in a cure rate above 85% according to reports from global TB programmes, yet rates of TB screening in people with HIV are low.

People with HIV are not being offered isoniazid preventive therapy on the scale necessary to prevent new cases of TB in people previously exposed to TB, and the provision of antiretroviral therapy is failing to keep pace with HIV diagnoses in TB cases, the WHO report notes.

WHO says that although the estimate of TB deaths is double the number it published in 2006, this does not represent a doubling in TB cases since 2006. Instead, the organisation’s epidemiologists believe their new estimate is a more accurate picture of the global TB burden among people with HIV, because it draws on findings from more extensive HIV testing among people diagnosed with TB in 64 countries during 2007-2008.

Of the fifteen countries with the highest incidence of TB in HIV-positive people, all but one are in sub-Saharan Africa, with southern Africa leading the way.

In Lesotho, Swaziland, South Africa, Zimbabwe, Namibia and Botswana the incidence of HIV-positive TB cases is above 400 cases per 100,000 people, while the prevalence of HIV in new TB cases is above 50% in the southern African region. Overall, 79% of HIV-positive TB cases are estimated to occur in sub-Saharan Africa.

WHO says that overall progress towards diagnosing HIV in TB patients is good, with 14 African countries able to report the HIV status of more than half of TB cases in 2007.

Nevertheless WHO estimates that only 37% of notified TB cases across Africa as a whole were tested for HIV in 2007, and HIV case detection in DOTS programmes (directly observed treatment) needs to be expanded.

However TB screening among people already diagnosed with HIV continues to be low, WHO says, and provision of isoniazid preventive therapy is extremely limited: only 30,000 people with HIV are estimated to have begun a course of isoniazid in 2007 (4.8% of those eligible) and just 14% of HIV-positive people in care have been screened for TB.

Provision of antiretroviral therapy to HIV-positive TB patients is also lagging behind rates of HIV diagnosis in TB patients. Just one-third of HIV-positive TB patients started antiretroviral therapy in 2007, perhaps because the number of health facilities offering antiretroviral therapy is not keeping pace with the expansion of provider-initiated counselling and testing in TB programmes.

WHO estimates that there were five TB treatment facilities for every ARV clinic in eight focus countries that account for 18% of global HIV-positive TB cases in 2007.

WHO also reported on progress towards integration of TB/HIV activities at country level, and collated monitoring data on implementation of some key actions it recommended in 2007 called the Three I’s – intensified case finding, isoniazid preventive therapy and infection control - that are aimed at reducing the burden of TB in people with HIV.

While 156 countries got a 90%+ score for their completeness of reporting on mechanisms for collaboration and joint policy development, when it came to the practical fruits of this policy work, more than half of countries filed seriously incomplete details of their progress towards intensified TB case finding in people with HIV or provision of isoniazid preventive therapy. Details of infection control activities were also frequently lacking.