Why an Ebola outbreak could never happen in the U.S.

Ebola virus disease (EVD) in Western Africa is spreading rapidly. More than 2000 people have died, and the number of infections has doubled over the last month. Model projections suggest that if unchecked, tens of thousand, and maybe even hundreds of thousands of people could die. Fortunately, the World has finally grasped the enormity of this tragedy. On Tuesday, President Obama announced that the U.S. would commit a significant amount of aid totaling up to $500 million and 3000 military personnel.

In his speech, President Obama mentioned national security as one justification for this action along with taking the lead during a humanitarian catastrophe, but in the same breath he asserted that an Ebola outbreak could never happen in America despite the slim possibility that an infected individual could board a plane and within hours land at a U.S. airport. The President is correct, the probability of a significant Ebola outbreak in the U.S. (or any country with a modern health system) is basically zero. There are 5 good reasons why EVD could never spread here.

1. Low transmissibility. This is the most important factor. Transmission of Ebola virus requires direct contact (e.g. via broken skin or mucous membranes) with blood or bodily fluids (e.g. saliva, urine, stool, vomit). Thus with proper protective garb, a person would be safe. Unlike the flu virus, Ebola virus is not airborne transmissible, e.g. respiratory droplets from a sneeze or a cough that can be breathed in. In addition, infectious patients can be quickly identified and isolated until they are cured (and are no longer infectious) or die. Furthermore, EVD is primarily contagious only when symptomatic, has a rapid onset, and if untreated, leads to a rapid death.

2. Early containment. Previous Ebola virus outbreaks were limited in size because they were contained early with a small number of cases. Problems arise when the number of patients outstrips the ability of the public health infrastructure to treat, isolate, and track them and the people they contact. Increased population density and better transportation has made early containment more challenging in Western Africa than previously. In the U.S. we would be able to quickly identify and isolate any infected individuals ensuring small numbers of patients.

3. Public health awareness. The literacy rate in Western Africa is very low. Many people are either unaware of EVD or do not properly understand the disease. Tragically, some have even attacked medical aid workers (NYTimes). In the U.S., tracking down infected people, and identifying and testing those who may have been in contract with them would be performed efficiently.

4. Superior health infrastructure. The hospitals in Western Africa are understaffed and poorly equipped. They have been overwhelmed by the onslaught of Ebola patients. Even basic sterilization of medical tools is suspect. America has the best hospitals and health infrastructure in the World. Good examples are Emory hospital which treated Dr. Kent Brantly and Ms Nancy Writebol, and more recently, the Nebraska Medical Center which is treating Dr. Rick Sacra (Figure 1).

5. Not poverty-stricken. The affected areas are some of the poorest regions in the World. Sanitation is inadequate and living conditions are crowded. Even disposing of the bodies has been an issue with touching of the bodies at funerals contributing to the spread of the disease. The U.S. is one of the wealthiest countries in the World, with excellent sanitation and living conditions by comparison.

Unless Ebola virus goes airborne, the chances of an outbreak in the U.S. (or any wealthy country) are negligible. The chance of Ebola virus going airborne is also negligible despite some fear-mongering in the press, but that is a topic for a future post.

Figure 1. Dr. Rick Sacra who contracted Ebola Virus Disease while treating patients in Liberia is expected to make a full recovery at Nebraska Medical Center in Omaha.