Global Burden of TB Higher Than Thought

Megan Brooks

October 22, 2014

New, intensive efforts in recent years to improve collection and reporting of data on tuberculosis (TB) are ratcheting up concern over the epidemic, revealing there are nearly half a million more cases of the disease than previously estimated, the World Health Organization (WHO) said today.

WHO's "Global Tuberculosis Report 2014" shows that 9 million people developed TB in 2013, and 1.5 million died.

The report also notes that the mortality rate from TB is still falling and has dropped by 45% since 1990, whereas the number of people developing TB is declining by an average of 1.5% a year. An estimated 37 million lives have been saved through effective diagnosis and treatment of TB since 2000, the WHO said.

An estimated 1.1 million (13%) of the 9 million people who developed TB in 2013 were HIV-positive, according to the WHO, with the number of TB deaths among HIV-positive people falling from 540,000 in 2004 to 360,000 in 2013.

Multidrug-Resistant TB Crisis Continues

"Following a concerted effort by countries, by WHO and by multiple partners, investment in national surveys and routine surveillance efforts has substantially increased. This is providing us with much more and better data, bringing us closer and closer to understanding the true burden of tuberculosis," Mario Raviglione, MD, director of the Global TB Programme, WHO, said in a prepared statement.

The report notes that the global health community has made "considerable" progress responding to multidrug-resistant tuberculosis (MDR-TB), yet it remains "far from sufficient."

The MDR-TB "crisis" continues, the WHO said. Worldwide, about 3.5% of all people who developed TB in 2013 had MDR-TB. Some countries have "severe epidemics" of MDR-TB and "alarmingly low" treatment success rates, the report notes.

Furthermore, extensively drug-resistant TB has now been reported in 100 countries.

In 2009, the World Health Assembly called for universal access to diagnosis and treatment of MDR-TB, which contributed to a sharp increase in cases detected and treated. In 2013, 136,000 MDR-TB cases were detected, up from 52,825 in 2009, and 97,000 people were started on treatment, up from 30,500 in 2009.

"Although the number of patients treated has increased three-fold since 2009, at least 39,000 patients, diagnosed with this form of TB, were not being treated last year and globally only 48% of patients were cured," the WHO said in a statement.

"The progress that has been made in combatting MDR-TB has been hard won and must be intensified. Containing and reversing the epidemic requires immediate and sustained efforts by all stakeholders," Karin Weyer, PhD, WHO coordinator for laboratories, diagnostics, and drug resistance, said in the statement.

Increased Commitment Needed

"Improved diagnostic tools and access mean that we are detecting and treating more cases. But the gap between detecting and actually getting people started on treatment is widening and we urgently need increased commitment and funding to test and treat every case. In countries such as Estonia and Latvia, where there is universal access to rapid diagnostics and treatment, the number of MDR-TB cases has fallen significantly. This shows what can be achieved," Dr Weyer said.

Currently, data on drug resistance are available for 144 countries, which collectively have 95% of the world's population and TB cases. "This shows impressive progress; in the period 1994–1999, data were available for only 35 countries with 20% of the world's population and 16% of the global TB burden," the WHO said.

Levels of drug resistance among new cases are less than 3% in 108 (75%) of the 144 countries with drug resistance surveillance data. This includes almost all countries in the Region of the Americas, most countries in the African and Southeast Asia regions, most countries in Western Europe, and several countries in the Western Pacific Region.

Eastern European and central Asian countries have the highest levels of MDR-TB, reaching 35% of new cases and 75% of previously treated cases in some settings, the WHO said.

More than half of the global burden of MDR-TB is in three countries: India, China, and the Russian Federation.

The WHO said rapid molecular tests are now being incorporated into drug resistance surveillance programs, which are expanding to cover more drugs.

"To date, surveillance has focused primarily on resistance to rifampicin and isoniazid, the two most powerful first-line anti-TB drugs. Fluoroquinolones (FQs) and pyrazinamide (Z) are key drugs being tested as part of new TB and MDR-TB regimens. Understanding the background prevalence of resistance to these drugs is essential," the WHO said.

In 2013, five countries started monitoring for resistance to FQs and Z (Azerbaijan, Bangladesh, Belarus, Pakistan, and South Africa), and surveillance will expand to more countries in 2015.

Preliminary results from the five countries show that resistance to rifampicin is often associated with resistance to Z. Resistance to ofloxacin (one of the FQs) is generally lower than rifampicin resistance, except in Asian countries in which FQs are extensively used, the WHO said.

Five Action Points

The agency said five priority actions are "crucial" to accelerate the response against the MDR-TB epidemic:

  • Prevent MDR-TB as a first priority.

  • Scale up rapid testing and detection of all MDR-TB cases.

  • Ensure prompt access to appropriate MDR-TB care, including adequate supplies of quality drugs and scaled-up country capacity to deliver services.

  • Prevent transmission of MDR-TB through appropriate infection control.

  • Underpin and sustain the MDR-TB response through high-level political commitment, strong leadership across multiple governmental sectors, ever-broadening partnerships, and financing for care and research.

"In addition to the serious under funding for research, US$ 8 billion a year is required for TB and MDR-TB prevention, diagnosis and treatment. Domestic and international financing needs to step up to prevent millions of unnecessary deaths," said Katherine Floyd, WHO coordinator for TB monitoring and evaluation.

Dean Schraufnagel, MD, past president of the American Thoracic Society (ATS), stressed the need for more funding.

"While the overall mortality rate from TB has dropped by 45 percent since 1990, we note with concern the reported increase in TB deaths last year and the continued spread of [MDR-]TB. The WHO's report also points out that 3 million people with TB are still being 'missed,' because they are not identified and treated for TB. The ATS reiterates its call to the international community to fully fund TB control and research and development programs," he said in a prepared statement.

"Global Tuberculosis Report 2014." WHO. Full text

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