Tuberculosis (TB) is the leading killer of HIV-positive people globally. Almost 15 years ago the World Health Organization (WHO) and UNAIDS recommended that people living with HIV be given isoniazid preventative TB therapy (IPT), to prevent active TB, but national implementation of IPT has been slow.
IPT, intensified TB case finding, and infection control are now the World Health Organization’s three strategies for reducing TB among people living with HIV, also known as the "Three I's for HIV-TB."
IRIN/PlusNews charts the uneven adoption of TB preventative therapy in southern Africa, which has the unhappy distinction of bearing some of the world's highest HIV and TB burdens.
After rolling out IPT at three pilot sites, the country began a national IPT rollout in 2001 that allows for symptomatic TB screening to rule out active TB as a prerequisite for IPT. By 2005 IPT was being offered alongside voluntary HIV testing and counselling, antiretroviral (ARV) treatment and prevention of mother-to-child HIV transmission services, although pregnant women and children under 16 are not eligible for IPT in Botswana.
Three years later, doctors and nurses were prescribing IPT at more than 600 health facilities, according to the Botswana Ministry of Health. By 2007 the country's IPT programme had enrolled about 72,000 eligible patients.
In 2009, a clinical trial conducted in Botswana found that taking IPT for 36 months prevents significantly more cases of TB in people living with HIV than simply taking a short course of IPT for six months.
Like neighbouring South Africa, Zimbabwe and Namibia, all HIV/TB co-infected patients are eligible for HIV treatment, regardless of their CD4 count (a measure of the immune system's strength).
As of September 2011 the country had not yet implemented IPT, but was set to finalize draft national guidelines.
The WHO estimates that the country accounts for about 2 percent of HIV-TB co-infected patients globally. Malawi has adopted IPT and uses symptomatic screening to rule out active TB, but guidelines recommend that IPT be stopped in patients who recently started taking ARVs. All HIV-positive patients are started on ARVs if they are diagnosed with TB.
The country carried about five percent of the global HIV-TB burden in 2010, according to WHO. In recent years it embarked on an aggressive scale-up of IPT provision, and increased the number of HIV patients on IPT almost 20-fold between 2008 and 2010. TB screening of HIV-positive people shot up 60 percent in the same time. In 2011 the country disseminated updated IPT guidelines, but is not yet completely in line with WHO recommendations because it does not prescribe IPT to pregnant women.
|Preventative TB trial disappoints|
|What the world's largest preventative TB study taught us|
|Reducing TB a matter of life and death|
|TB and HIV coinfection a bigger threat|
IPT has been rolled out to HIV patients and others who have been in close contact with someone recently diagnosed with active TB. To qualify for IPT, people living with HIV must meet specified requirements - for example, they must be relatively healthy, with no history of alcoholism or liver disease. HIV-positive children also qualify for IPT, provided they have never received it previously and have not had active TB in the last two years.
HIV-negative children up to five years of age who have been in close contact with someone who has active TB and is still infectious also qualify for IPT, as do adults who have been in contact with such a person and have compromised immune systems due to conditions like diabetes and leukaemia. However, as the country's 2011 national HIV strategic plan notes, IPT implementation and monitoring have been limited by the lack of a dedicated plan to track HIV-TB services.
About 60 percent of TB patients are co-infected with HIV and so are eligible for treatment regardless of their CD4 count. All people living with HIV are eligible for ARVs if they are diagnosed with TB.
Almost 300,000 people were co-infected with HIV and TB in 2010. The country is estimated to account for about 24 percent of the world's HIV-TB burden, according to the WHO.
South Africa has had national guidelines for administering IPT since 2002, but coverage remains low, partly due to a lack of awareness among health care providers, according to small qualitative studies by the Aurum Institute, a South African health research organization.
The country's recent large-scale IPT trial among gold miners failed to prove that community-wide IPT worked better than the recommended targeted provision to high risk groups, but did demonstrate IPT's protective benefits against active TB.
The Aurum study also confirmed that IPT reduces the risk of death for people living with HIV by halving the risk of dying in HIV-positive patients on or just starting antiretrovirals (ARVs). Based on this finding, South African guidelines no longer discourage the use of IPT in ARV patients.
In a country where about 85 percent of TB patients are co-infected with HIV, health workers use symptomatic screening to rule out active TB and prescribe IPT. In 2009 about 2,000 HIV patients received IPT, according to a report by the HIV/AIDS news service, Aidsmap.By 2010 Swaziland accounted for about 1 percent of the world's HIV-TB co-infection cases.
National guidelines were drafted in 2010, allowing health workers to prescribe IPT for HIV patients without signs of active TB. While Zambia lagged behind the region in adopting IPT, its decision to recommend IPT for national use was bolstered by the use of IPT in the large-scale TB prevention ZAMSTAR clinical trial, which took place in Zambia and South Africa. About 23,000 people, or 2 percent of the global HIV-TB burden, is in Zambia.
An estimated 4 percent globally of the people co-infected with HIV and TB live in Zimbabwe. Although the most recent TB control guidelines do not recommend the use of IPT, in 2011 the country was in the process of developing national IPT guidelines.