Zimbabwe: Improved treatment coverage cuts TB rates

12 October 2016

Expanding access to treatment for people living with HIV is shown to decrease tuberculosis (TB) incidence – but it is not the silver bullet.

A nurse distributing TB treatment

Increasing access to antiretroviral treatment (ART) for people living with HIV in Zimbabwe has dramatically reduced rates of tuberculosis (TB) in the country. As treatment coverage rose from less than 0.5% in 2004 to just under half (48%) in 2013, cases of TB fell markedly from 450 per 100,000, to less than 250 per 100,000.

Tuberculosis is one of the leading causes of morbidity and mortality for people living with HIV globally – accounting for around one third of the 1.2 million people living with HIV who died in 2015.

The data, published in the journal Public Health Action, provides further evidence on the benefits of antiretroviral therapy to reduce the burden of TB among people living with HIV. While the study cannot show direct causality, it is likely that the decline in TB incidence is due to the protective effects of ART for people living with HIV, who are more susceptible to TB due to a weakened immune system.

In fact, modelling data from nine other sub-Saharan African countries suggests that giving treatment to people living with HIV immediately could avert over a third of new TB cases by 2050 in the region.

In an accompanying editorial, Nathan Ford and Haileyesus Getahun of the World Health Organization (WHO) note that while the data provides an important incentive for treatment expansion, it is not the only intervention needed to curb HIV-associated TB.  
In light of the new WHO guidelines, which call for all people living with HIV to be on treatment, regardless of disease progression, reducing TB incidence may only happen if people access treatment quickly, and it is effective.

They also note the importance of education and awareness building among people living with HIV about how TB is transmitted, particularly transmission of airborne TB in certain settings. Expanded access to isoniazid preventive therapy (IPT) to treat TB is also critical – it has been shown to decrease TB incidence independent of ART. Lastly, HIV and TB programmes should be delivered jointly, to maximise the impact of both interventions.

Ford and Getahun conclude: “This study shows encouraging national trends of decreasing TB case notification rates that support the continued scale-up of ART to PLHIV as a means of tackling the twin epidemics of TB-HIV/AIDS in Zimbabwe.”

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