Federal officials and elite public health experts say that the guidelines published by the Centers for Disease Control are “science-based.” A close look at those guidelines suggests that the scientific foundation is not much different from that which some states have relied upon. The difference concerns the amount of public health precaution included in their respective risk management policies.
“High risk” is a rare category; it requires unambiguous exposure to a person known to be contagious resulting from failure to correctly use appropriate personal protective equipment. Persons defined as “low risk” include those who have traveled “in a country with widespread Ebola virus transmission” but “hav[e} had no known exposures,” those who have had “brief direct contact” with a person with Ebola in “the early stage of the disease,” or traveled on an aircraft with a person with symptomatic Ebola.
Few health care workers returning from West Africa, or serving contagious Ebola patients in the US, would likely say they are “high risk.” They would be assigned to the “some risk” category.
These distinctions are impossible to make objectively because doing so requires knowledge of unobservable facts. For example, all three of the active US health worker cases probably believed they had taken all appropriate precautions.
Whether they were classified as “high risk” or “some risk” makes no difference because the CDC’s risk management recommendations are the same for both. Those who display a temperature ≥100.4°F (temporal, oral or rectal, it does not say), or any one of six other symptoms, are deemed “symptomatic” and are subject to quarantine unless and until Ebola is ruled out as the cause. CDC does not use the word quarantine, however, preferring instead the laborious phrase “rapid isolation with immediate contact of public health authorities to arrange for safe transport to an appropriate healthcare facility for Ebola evaluation.”
Likewise, asymptomatic persons in the two highest risk categories are subject to virtually the same risk management recommendation — “direct active monitoring” and extensive travel restrictions, notably exclusion from work and any other place where people congregate. The CDC does not use the term travel restrictions, either, preferring to describe them as “controlled movement” and “exclusion from public places.”
Semantic distinctions aside, CDC’s recommendations permit substantial discretion on the part of state and local authorities. In particular, they imply broad discretionary authority to make clinical judgments and case-by-case decisions, including involuntary quarantines:
The temperature and symptoms thresholds provided are for the purpose of requiring medical evaluation. Isolation or medical evaluation may be recommended for lower temperatures or nonspecific symptoms (e.g., fatigue) based on exposure level and clinical presentation.
The quarantines imposed by several governors are not inconsistent with CDC guidance and recommendations. They may involve more precautionary risk classification assignments, such as for example assuming that personal protective equipment may have failed in the absence of proof that it did not. And they also may involve more precautionary risk management decisions in the absence of proof that less precautionary approaches would be successful. Finally, the settings vary in which these risk management decisions must be made. More stringent practices may well be necessary to achieve the same level of public health protection in metropolitan New York than in northern Maine.
In short, there is little apparent difference between the CDC guidance and recommendations and the practices of the states. The predominant differences are matters of policy.
- High risk includes any of the following:
- Percutaneous (e.g., needle stick) or mucous membrane exposure to blood or body fluids of a person with Ebola while the person was symptomatic,
- Exposure to the blood or body fluids (including but not limited to feces, saliva, sweat, urine, vomit, and semen) of a person with Ebola while the person was symptomatic without appropriate personal protective equipment (PPE),
- Processing blood or body fluids of a person with Ebola while the person was symptomatic without appropriate PPE or standard biosafety precautions,
- Direct contact with a dead body without appropriate PPE in a country with widespread Ebola virus transmission,
- Having lived in the immediate household and provided direct care to a person with Ebola while the person was symptomatic
- Some risk includes any of the following:
- In countries with widespread Ebola virus transmission: direct contact while using appropriate PPE with a person with Ebola while the person was symptomatic
- Close contact in households, health care facilities, or community settings with a person with Ebola while the person was symptomatic
- Close contact is defined as being for a prolonged period of time while not wearing appropriate PPE within approximately 3 feet (1 meter) of a person with Ebola while the person was symptomatic
- 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
- 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.
- No identifiable risk includes:
- Contact with an asymptomatic person who had contact with person with Ebola
- Contact with a person with Ebola before the person developed symptoms
- Having been more than 21 days previously in a country with widespread Ebola virus transmission
- Having been in a country without widespread Ebola virus transmission and not having any other exposures as defined above.