Sunday, November 2, 2014

CDC now admits there IS a (low) risk of infection, if you are on a plane or in a room with a symptomatic Ebola patient/ CDC

CDC changed its story again.  As of October 27, CDC updated its risk guidelines to acknowledge that being in a room or on a plane with someone who is symptomatic with Ebola puts others at low, but not zero, risk of contagion.  I applaud CDC for this change.  It admits there is much we do not understand about Ebola transmission.  I too believe the risk in these situations is low, but real.

There is another new admission here that I missed, earlier.  This one says that there is a risk of Ebola transmission from shaking hands with someone before they are clinically ill, or as CDC puts it, "in the early stage of disease."  Previously CDC has insisted that you need to be sick to transmit Ebola, so sick that most victims would seek medical care, and not attend social events.  This admission finally allows for nuance:  no one can say with 100% certainty when someone will be contagious, as infectiousness develops on a continuum, as viral counts rise.

How contagious is Ebola?

Surprisingly, Ebola is not that contagious.  Each person only gives it to 1.7-2 other people, on average.  That is far less contagious than colds, flu, or measles.

The problem with Ebola is that who gets the disease is unpredictable.  Of those people exposed to the virus, it seems that only a small number actually get sick.  But it is impossible to predict who they will be.

How do people think they got it?

NBC cameraman Ashoka Mukpo believes he got it from spray when cleaning a car that an Ebola patient had ridden in.  Nancy Writebol suspects she got it from touching something that was touched by a man who had Ebola. Dr. Kent Brantly suspects he got it when attending to a patient who was believed to have a different problem, when he was not wearing all his protective gear.

How can you separate the patients without Ebola from those with Ebola?

There’s the rub.  The test may not be accurate early in the course of disease.  Patients can have 2 diseases simultaneously.  Nancy Writebol tested positive for malaria, which she had had before.  She was initially treated for malaria.  Only when she failed to get better was she tested for Ebola. Yet her husband and others who had close contact with her during the time she seemed to have malaria never developed Ebola.

How can you safely treat people for other illnesses in west Africa right now?

I don’t have an answer.  Must you wear PPE for each patient?  That means you must put it on and take it off between patients, which may take ½ hour.  Can clinics afford the costs of treating every condition with a new set of PPE? For these reasons, Ebola may logistically destroy the provision of all other healthcare in affected regions.

CDC has tacitly acknowledged the serious problem of not knowing for which patients elaborate PPE needs to be worn, in guidance issued Oct. 28.  CDC attempts to solve this conundrum by asking that emergency dispatchers (who usually have no medical training) ask questions about exposure to someone with Ebola, and travel to west Africa, when they get a call requesting an ambulance.

However, this is only effective if dispatchers are capable of identifying early Ebola symptoms (like a headache or fever), which is impossible.  The guidance also assumes people will be completely honest. The truth is that we will have no foolproof way to protect EMS personnel if Ebola breaks out in the US.

HERE is the CDC definition of a low risk exposure to Ebola:
  1. Low (but not zero) risk includes any of the following:
    • Having been in a country with widespread Ebola virus transmission within the past 21 days and having had no known exposures (This would include the US' UN ambassador, Samantha Power)
    • Having brief direct contact (e.g., shaking hands) while not wearing appropriate PPE, with a person with Ebola while the person was in the early stage of disease
    • Brief proximity, such as being in the same room for a brief period of time, with a person with Ebola while the person was symptomatic
    • In countries without widespread Ebola virus transmission: direct contact while using appropriate PPE with a person with Ebola while the person was symptomatic
    • Traveled on an aircraft with a person with Ebola while the person was symptomatic.
Thanks to Diane Irving for pointing this out.

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