Amesh A. Adalja, MD, FACP, FACEP, October 22, 2014
This week brought the end of the 21-day observation period of the contacts of Thomas Eric Duncan, the first Ebola patient diagnosed in the US. None of his initial contacts, including close family members, became ill—a fact that underscores important elements of Ebola’s transmission characteristics.
The contagiousness of Ebola is directly related to the amount of blood and bodily fluids emitted from patients, as contact with these substances is the sole proven means of infection. As vomiting, diarrhea, and hemorrhage worsen during the course of illness, contagiousness accordingly rises. Such differential contagiousness may explain the absence of illness among Mr. Duncan’s initial contacts. As Mr. Duncan’s condition worsened, later contacts would have been exposed to progressively more infectious material. This scenario, coupled with the initiation of invasive medical procedures such as hemodialysis and mechanical ventilation, would have conferred a much higher risk of contagion on those exposed to him in the later stages of illness, such as healthcare workers with less than optimal use of personal protective equipment (PPE).
Reflecting the newly appreciated realization that healthcare workers in industrialized countries may paradoxically have a heightened risk of infection, the CDC issued revised PPE guidance with 3 overarching principles: training with drills, no skin exposure, and monitoring of proper donning and doffing procedures. The guidance was informed by best practices used at the sophisticated biocontainment facilities at the NIH, Emory University Hospital, and Nebraska Medical Center, where several Ebola patients have been successfully cared for without any resulting healthcare worker infections.
The fact that 2 American healthcare workers were infected with Ebola has highlighted a severe shortcoming in infection control procedures that is undoubtedly present in many other hospitals across the nation. Unfortunately, nationwide, infection control is practiced with varying degrees of rigor and with little formal training, even at tertiary care academic medical centers. The result of suboptimal infection control practice is usually not immediately obvious for most pathogens—that is, the healthcare workers do not get overtly sick with a highly lethal disease. Ebola, much like SARS 11 years ago, is the exception that demonstrates what actually happens all the time. Without extensive training, practice, and meticulous attention to detail, healthcare workers are exposed to contagious pathogens all the time. Furthermore, the vast majority of healthcare workers in the US have little or no experience with donning and doffing the newly recommended full body suits, even though they may be part of a cadre of personnel designated in advance to care for an Ebola patient.
Infection control guidance that is not coupled with extensive training will continue to place healthcare workers at risk. Treating an Ebola patient safely requires meticulous adherence to protocol that can only be achieved by repeated training, practice, and drills. Just-in-time training to use the extensive PPE required to care for a patient safely cannot alone be expected to produce proficiency.
Juxtaposing the experience of Dallas with that of the biocontainment facilities leads to the conclusion that future Ebola cases in the US should optimally be managed at one of the existing 4 biocontainment facilities, so long as capacity exists. This should be the first tier of a national response strategy. If the capacity of these facilities is exceeded, other designated regional facilities, which have incontrovertibly demonstrated their proficiency with infection control and are augmented by CDC and Department of Defense support and training, should be used as a second tier. Unless there is a large epidemic, which is very unlikely, ordinary hospitals should not provide care for Ebola patients beyond initial evaluation and diagnosis.
Ensuring infection control protocol adherence is paramount to containing this outbreak in all settings.