Costs and Benefits of Quarantine and Isolation


Clearly, at least in the US, ebolaphobia has been contagious.  But lets look at the concepts of quarantine and isolation.  According to CDC:

  • “Isolation separates sick people with a contagious disease from people who are not sick.
  • Quarantine separates and restricts the movement of people who were exposed to a contagious disease to see if they become sick.”

I want to focus on the concept of quarantine.  The operative phrase in the CDC definition is “who were exposed to a contagious disease”.  What precisely does that mean — is it that they are almost certain to progress to illness (i.e., the level of exposure was sufficiently high to give a near 100% probability), or that they were in circumstances where they could have received a dose (but they have perhaps a less, or much less probability of progressing to illness)?

There are clear costs and potential benefits to quarantine.  The obvious costs include the following:

  • lost wages for individuals unable to work during the quarantine period
  • room and board if the quarantine is not home quarantine
  • medical monitoring
  • costs associated with enforcement
  • there is the less tangible, but nonetheless real, cost of reducing civil liberties of the affected persons
  • for quarantine of health care workers after they have cared for patients (either in Africa or domestically) there is the cost that is also not well quantifiable in deterring others from giving such vital services in the future.

There are also potential benefits, which may be more difficult to calculate.  For the fraction of individuals who will succumb to disease, placing them in quarantine may reduce the spread of disease in others.  But to adequately quantify this one needs to employ a disease transmission model, which will require estimation of the underlying parameters, and also the underlying baseline disease prevalence.

Right now rather than such rational decision making, the mad rush towards quarantine seems to be political.  The general consensus seems to be that a signal early symptom of Ebola is a rapid onset of fever.  Therefore, if a person is deemed to be responsible (and presumably a default ought to be that health care workers are regarded as such), self monitoring and reporting is sufficient.

It seems to be unfortunate that decision making now has a strong element of science denial.