SOUTHERN AFRICA: HIV testing and treatment to prevent TB
TB often goes undetected in HIV-infected patients
Johannesburg, 19 May 2010 (IRIN) - Diagnosing HIV early and starting antiretroviral (ARV) treatment could be the most important weapons in the battle against HIV-associated tuberculosis, but this would need a huge injection of resources in southern Africa, where the dual epidemics of TB and HIV claim the most lives.
The authors of a paper
, part of a series on TB in the British medical journal, The Lancet, note that the disease accounted for more than a quarter of the two million deaths attributed to AIDS-related diseases in 2008, and is the number one cause of illness and death in people living with HIV in Africa, yet efforts to contain TB-HIV co-infection have been "timid, slow and uncoordinated".
A move towards earlier HIV testing and treatment is already underway. Many countries have adopted the 2009 World Health Organisation (WHO) guidelines
, which raised the threshold for starting ARV treatment from a CD4 count of less than 200, to 350.
Earlier ARV treatment as a tool to prevent TB has received less attention, but the reality is that "Many people with HIV infection start ART [antiretroviral therapy] too late, especially in Africa, and have already developed TB by the time that they present to health services for care," the authors said.
Prof Anthony Harries, a senior adviser to the International Union Against Tuberculosis and Lung Disease and lead author of the paper, welcomes the WHO guidelines but supports the more radical approach, yet to undergo field trials, of testing all adults for HIV once a year and immediately starting everyone who tests positive on ARVs.
This strategy, based on findings from a mathematical model
published in The Lancet in November 2008, could reduce HIV prevalence to less than 1 percent within 50 years in a country with a generalized epidemic such as South Africa.
Using the same model, Harries and his co-authors estimated that the incidence of HIV-related TB could be more than halved if ARV treatment were started within five years of infection.
Studies to test the efficacy of such an approach still need to be done, but Harries believes it is feasible "if decision-makers are prepared to think and act out of the box".
The upfront costs would be significant, and donors appear to be decreasing or flat-lining their support for HIV/AIDS treatment as a result of the global economic slowdown, but Harries pointed out that a universal test-and-treat approach would result in cost savings in the long term.
"It would not be easy but, if you go back five years, ART scale-up wasn't easy and there was a lot of opposition, but we had good, clear leadership from the WHO," he told IRIN/PlusNews.
In the absence of early HIV diagnosis and treatment, The Lancet paper argues that many lives could be saved by better implementation of a policy for preventing HIV-associated TB known as the 3Is: Intensified TB case-finding, Infection control, and Isoniazid preventive therapy.
One of the main difficulties in implementing the 3Is has been diagnosing TB in HIV-positive patients, particularly in low-income countries that lack the equipment to conduct culture testing - the most reliable way to diagnose TB, in which samples are cultivated in a special liquid.
Problematic diagnosis has in turn hampered the use of Isoniazid to treat latent TB infection. Fear of creating drug resistance by prescribing it to patients with undetected TB has meant that Botswana is the only country in southern Africa to have incorporated this approach into its national TB policy.
Harries, who has worked as a technical adviser to Malawi's HIV/AIDS department and its TB control programme, said HIV programmes should take responsibility for implementing the 3Is by ensuring that patients diagnosed with HIV received regular care before starting ARV treatment.
"In most of poor Africa, you get HIV tested and maybe don't even get a CD4 count, so somebody does a clinical assessment and decides if you're stage 3 or 4 [when ARV treatment usually starts]. If you're stage 1 or 2 [asymptomatic], then basically you're told, 'Go away and we'll see you when you're sick'," he said.
"We need pre-ART care: a clinic where people would come every three months to be checked and given co-trimoxazole [an antibiotic that helps prevent opportunistic infections] or Isoniazid."
A more innovative but as yet untested approach, which Harries and his co-authors propose in The Lancet paper, would be providing TB treatment to all HIV-infected patients who are sick and have low CD4 counts.
"We know it's difficult to diagnose TB in [a low-income] setting," he said, but by putting such patients on TB treatment, "you stop that person transmitting TB every time he comes to the clinic, and if he hasn't got TB, this is a very good preventive therapy."
Harries urged greater collaboration between TB and HIV programmes. "In the HIV/AIDS world, activism has played such a big part; in the TB community we're not good at that. We need to get TB patients who've been cured, who are articulate, and they need to be advocates for TB and work with HIV activists to tackle policy-makers."