Can New Zealand stop drug-resistant TB too?

This World Tuberculosis (TB) Day (24 March) is another opportunity for people of New Zealand to review their TB responses. Drug susceptible TB is treatable, curable and with proper programme interventions, it is possible to believe in the theme of World TB Day: 'I can stop TB'. Can we say the same for drug-resistant TB?

Drug-resistant TB has been recorded in the world at the highest levels ever according to the World Health Organization (WHO) report (Anti-Tuberculosis Drug Resistance in the World, February 2008).

DOTS (directly-observed treatment short-course), is the internationally recommended TB control strategy that includes standardized case detection, treatment and patient support. It requires consistent drug supply and effective monitoring systems. According to WHO, drug resistant TB is a symptom of poor programme performance. If we hope to change the outcome, and decrease the proportion of drug resistant TB, doesn't the DOTS model need to be adapted or its implementation improved? More of the same might only compound the TB drug resistance threat.

The African, South-East Asian and Western pacific regions account for 83% of total TB case notifications according to the Global Tuberculosis Control report of WHO (March 2008). China, India and Indonesia are home to two-in-three of the world's TB cases. The Africa region has the highest TB incidence rate. These countries are expanding coverage of its TB programme at record-breaking speed. In its shadow, drug resistance is also upping the pace.

The proportion of resistance to at least one anti-TB drug (any resistance) was found to be as high as 56.3% in Azerbaijan.

Multi drug-resistant TB (MDR-TB) is defined as TB with resistance to isoniazid and rifampicin, the two most powerful first line anti-TB drugs. MDR-TB patients have significantly poor outcomes than patients with drug susceptible TB.

Global estimates indicate that 4.8% of TB cases were of MDR-TB (about half a million MDR-TB patients). Currently treatment is available only to one out of ten MDR-TB patients and 90% of MDR-TB patients cannot have access to treatment they need today.

About 50% of MDR-TB cases are in India and China because of large population. In Africa, hard-hit by HIV, the proportion of TB drug-resistance is no less alarming. In former Soviet Union, almost half of all TB cases are resistant to at least one anti-TB drug and every fifth case of TB will be of MDR-TB.

Extensively drug-resistant TB (XDR-TB) is virtually untreatable and likely to emerge where second-line anti-TB drugs are widely and inappropriately used. XDR-TB is more expensive and difficult to treat than MDR-TB and outcomes for patients are much worse with mortality rates very high. So far 46 countries have reported XDR-TB with UK reporting the first XDR-TB case last week.

Studies suggest that transmission of TB, especially the drug-resistant strains is more likely to take place where people living with HIV (PLHIV) congregate. Healthcare settings, for example those for anti-retroviral (ARV) delivery, is one such place where improper infection control can put PLHIV at risk of contracting TB. TB is the most common opportunistic infection and leading cause of death for PLHIV. Improving infection control in healthcare settings is clearly vital, doable and potentially life saving.

In many countries insufficient laboratory capacity to test drug-resistance is a serious impediment in scaling up TB programmes. Even the new WHO report on TB drug-resistance had data only from 6 African countries because other countries had no laboratory capacity to provide data on anti-TB drug-resistance. Developing laboratories to provide rapid diagnosis of anti-TB drug-resistance, particularly for PLHIV, is of utmost importance to improve TB responses.

Not only more and better TB drugs and diagnostics in the public sector are urgently needed but also better strategies to make TB control programmes work more effectively for the most vulnerable and hard to reach communities are essential to improving treatment adherence and, as a consequence, reducing drug resistance.

(Bobby Ramakant is a HDN Key Correspondent, email: info@thecorrespondent.org, website: www.TheCorrespondent.org)

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