It now turns out that the XDR-TB case which caused such an uproar last month (see our posts here) wasn’t XDR-TB at all but MDR-TB, a treatable form of the disease:
Andrew Speaker was diagnosed in May with extensively drug resistant TB, based on an analysis of a sample taken in March by the U.S. Centers for Disease Control and Prevention. The XDR-TB, as it is called, is considered dangerously difficult to treat.
But three later tests have all shown Speaker’s TB to be a milder form of the disease, multidrug-resistant TB, a federal health official said on condition of anonymity before a news conference in Denver. (Washington Post)
Just to be clear. His TB isn’t milder. MDR stands for “multiple drug resistant” while XDR is “extensively drug resistant” (The technical definitions: MDR-TB is resistant to isoniazid and rifampicin; in addition, XDR-TB is resistant to at least one of three injectable second line drugs (capreomycin, kanamycin, and amikacin). MDR-TB isn’t a good thing to have, but it is treatable. XDR-TB often isn’t. So getting the diagnosis right is not just important, it’s a matter of life and death. He was diagnosed with MDR-TB, for which he was under treatment, before he left for Europe. The “discovery” that it was the XDR form came after he was there. At that point there is evidence of confusion if not panic at CDC, where the supposed diagnosis was made on the basis of laboratory tests.
But three later tests have all shown Speaker’s TB to be a milder form of the disease, multidrug-resistant TB, a federal health official said on condition of anonymity before a news conference in Denver.
“Laboratory tests conducted at National Jewish Medical and Research Center indicate that patient Andrew Speaker’s tuberculosis is susceptible to some of the medication previously thought ineffective against his disease,” the hospital said in a written statement.
An about-face on the XDR diagnosis would be a major embarrassment for the CDC. The diagnosis was a key factor in issuing a quarantine order on Speaker, who had traveled to Greece to be married in May despite warnings from health officials that he shouldn’t travel.
On Tuesday, the CDC did not immediately clarify whether they were wrong in the earlier diagnosis or whether there are two conflicting results.
The failure to allow attribution by the unnamed “federal health official” suggests this is a CDC screw-up and they know it. Maybe not. Information and transparency from CDC would be useful. It is more evidence that things are not well at the agency, however. CDC has a powerful brand name as the most expert “disease detectives” in the country, if not the world. But under Director Gerberding much of that expertise has left, leaving a remnant and beleaguered cadre of dedicated professionals to fend for themselves amidst an institution crumbling around them.
What a pity.