TDR-TB and XXDR-TB: Frequently Asked Questions
Mandy Slutsker — January 26, 2012 – 5:35 pmWhat is TDR-TB?
The term totally drug resistant tuberculosis was invented by Iranian researchers in 2009 to describe a strain of TB that didn’t respond to treatment. Whereas people with MDR-TB (resistance to 2+ first line drugs) have a 30 percent chance of dying and people with XDR-TB (resistance to all first line and most second line drugs) have a 60 percent chance of dying, its believed that people with TDR-TB have a 100 percent chance of dying.
Is it really totally drug resistant?
It depends on who you ask. Many researchers say we can’t be sure it’s totally resistant because (1) there may be problems with drug susceptibility tests, (2) there is no standard protocol for diagnosing this strain, and (3) there are drugs currently in the pipeline that could potentially be effective against the strains of TDR-TB. However, researchers in India say their patients are resistant to all known forms of TB medication and therefore qualify as being ‘totally’ resistant.
Is there a WHO definition of TDR?
WHO does not have an official definition for TDR-TB, instead saying it’s probably best described as extra XDR-TB (hence XXDR-TB). The WHO plans to meet in March to discuss TB programs and potentially define TDR-TB and/or XXDR-TB.
Is the spread of infection any different?
No. People with pulmonary TB infect an estimated 10-15 people per year regardless of drug-resistance. TB has a higher chance of being spread when there is a higher concentration of people in places with poor ventilation, such as crowded houses, hospitals, or prisons.
What causes TDR-TB?
People with TDR-TB likely originally head XDR-TB that developed into a more resistant strain, possibly when a drug regimen was misused or mismanaged. Drug resistance can develop anywhere, but is more common in places TB control programs are managed poorly: poor patient support, low-quality health care, patients prescribed wrong treatment/wrong dose/wrong amount of time on treatment, insufficient supply of drugs, and insufficient quality of drugs.
Why now, why India?
India is home to 1/5 of the world’s TB cases, killing an estimated 1,000 people a day. While it’s National TB Program has been successful providing first line drugs to patients, many people in India seek health care from the unregulated private sector. One study showed only 5 of 106 private physicians prescribed appropriate drugs. Even if proper drugs are prescribed, many factors lead to people defaulting on their treatment. This is particularly in an issue for rural populations.
What can be done?
TB programs and strengthening and scaled up. Currently, TB programs all over the world face an $800 million funding gap - just for 2012. Eighty-six percent of TB financing comes from domestic budgets. The remaining 14 percent comes from donors. The Global Fund to Fight AIDS, Tuberculosis and Malaria is the largest external financer of TB programs. This week, as the Global Fund celebrates its 10th anniversary, its experiencing a major financing shortfall. We’re calling for an emergency donor conference to mobilize the resources needed to reverse the situation and provide for a new funding opportunity in 2012 and 2013. We’re also calling on the United States to convene donors before the International AIDS Conference, which takes place this July in Washington, D.C.
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