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Monday, August 11, 2014

Outbreak


In our politically polarized climate, the question of how best to treat two Ebola-infected medical missionaries has generated a false dichotomy. At one extreme is the shrewish reaction of Ann Coulter. At the other extreme I read a Christian pundit refer to "Ebola hysterics." 

But the real question isn't whether to treat them, but how and where. I'm no expert, but to my knowledge, containment (i.e. quarantine) is the first rule in preventing an epidemic. 

Ben Carson has raised concerns as well as proposing alternatives: 


Admittedly, Carson is not an infectious-disease specialist, and it's possible that he's wading into the controversy to raise his public profile as a presidential aspirant. At the same time, he is a respected medical professional–not some flake like Coulter or Trump.

Risk assessment is a twofold assessment:

i) What is the probability of exposure to the danger in question?

ii) What is the severity of the danger if exposed?

One has to balance these two factors. Something might be a low-risk in terms of probability, but high-risk in terms of severity if the worst-case scenario transpired. That's why we take extraordinary precautions with certain pathogens. Even if the risk of exposure is low, if the consequences of exposure are catastrophic, you err on the side of safety. 

Atlanta, where the CDC is located, is a huge metropolitan area with a major international airport. 

In addition, we have to ask how much faith we should put in medical professionals who work for the Federal gov't. I don't know the details, but don't Federal employees generally belong to public-sector unions whose contracts make it virtually impossible to fire them regardless of incompetence or misconduct? Indeed, they may even be promoted, or simply transferred to another department. 

It would be ironic if Christians, who are ordinarily skeptical of gov't, suddenly abandon their customary skepticism in this particular case. 

1 comment:

  1. In addition to the good and valid points Steve raised in his post:

    1. I think there's also a risk in terms of timing.

    Generally speaking, flu season is roughly from autumn to winter. For example, beginning in Oct, peaking Jan/Feb, and ending in March.

    Depending on the specific strain, the incubation period for Ebola is around two to three weeks. And it's a bit tricky to diagnose a person infected with Ebola since they initially appear quite similar to someone who has the flu.

    Why bring the two missionaries back home in August? What if Ebola begins to spread at the start of flu season and/or overlaps with flu season? The signal to noise ratio may be quite difficult to tease out.

    2. If I'm not mistaken, the CDC has repeatedly told the public Ebola is not airborne. For example:

    "Can Ebola be transmitted through the air? No. Ebola is not a respiratory disease like the flu, so it is not transmitted through the air."

    However, there are studies that have shown Ebola may in fact be airborne. See here for example:

    "The data on formal aerosol experiments leave no doubt that Ebola and Marburg viruses are stable and infectious in small-particle aerosols, and experience of transmission between experimental animals in the laboratory supports this [49, 56–63]. Indeed, during the 1989–1990 epizootic of the Reston subtype of Ebola, there was circumstantial evidence of airborne spread of the virus, and supporting observations included suggestive epidemiology in patterns of spread within rooms and between rooms in the quarantine facility, high concentrations of virus in nasal and oropharyngeal secretions, and ultrastructural visualization of abundant virus particles in alveoli [17, 50]. However, this is far from saying that Ebola viruses are transmitted in the clinical setting by small-particle aerosols generated from an index patient [64]. Indeed patients without any direct exposure to a known EHF case were carefully sought but uncommonly found [65]. The conclusion is that if this mode of spread occurred, it was very minor."

    At this point, while it's true airborne transmission appears rare, the possibility nevertheless exists. As such, it's at odds with what the CDC has informed the public.

    A larger point is we still have a lot to understand about Ebola. Which is perhaps another significant consideration to take into account.

    3. Some people think there's nothing to be concerned about Ebola because the CDC is near Emory University Hospital.

    Of course, the patients infected with Ebola aren't in the CDC. They're in Emory University Hospital. (Although CDC researchers are doubtless using the patients as live clinical subjects to better understand Ebola, etc.)

    By the way, to my knowledge, the CDC doesn't actually house the Ebola virus. Rather, I believe Ebola is at Fort Detrick (along with a lot of other scary stuff).

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