The WHO declared the end of the most recent outbreak of Ebola virus on July 2, 2017, saying two 21-day incubation cycles had passed since the last confirmed case in the Democratic Republic of the Congo. There were eight cases, four of whom died.
Meanwhile, the lessons of the epic 2014 Ebola outbreak continue to resonate, and among the most confounding of them is how to remove PPE after patient care without contaminating yourself in the process. Whether Ebola itself re-emerges, or some other infectious threat, it’s important to understand this difficult, multistep process and where these breakdowns occur, said Lisa Casanova, PhD, a microbiologist and assistant professor at Georgia State University in Atlanta.
“Experience has shown us that we don’t know what the next high-consequence pathogen is going to be. It could be any type of virus,” she said recently in Portland at the annual meeting of the Association of Professionals in Infection Control and Epidemiology. “I think it is important to instill these [Ebola] lessons because we never know when we are going to need this level of preparedness again. Also, a lot of the lessons we are learning about PPE I think are transferable to the ordinary health care setting. Also, the approach of understanding how well we are doing [with PPE] is transferable.”
Casanova and colleagues assessed viral self-contamination of skin and under clothes during removal of Ebola-level PPE after a simulated patient encounter using a surrogate solution to represent body fluids.1
“[The PPE] has done its job — it’s contaminated and you are not,” she said. “However, when you’re trying to get [the PPE] off, you are at risk for touching the pieces of PPE and contaminating yourself. You can contaminate what you’re wearing underneath. Doffing is a very complex process.”
Indeed, Casanova referred to a PPE removal protocol for Ebola doffing recommendations with 16 steps and multiple substeps.
“This [doffing] is all done with a trained observer who guides you through step by step, but a perfect process that prevents all contamination is not any good if nobody can do it consistently,” she said. “With PPE, it is often hard to tell how we are doing. Are we training people to do the right thing? It can’t be, ‘Well you must have done everything right because you didn’t get Ebola.’ We’ve got to do a little bit better than that. We asked whether we could simulate this complex process to figure out if it’s working. Also, simulation helps us figure out how people do real things that they do on the job, and the best thing is that we can actually understand disease transmission.”
Healthcare workers highly trained in PPE doffing were surreptitiously exposed to droplets from a solution containing bacteriophages — harmless viruses that infect bacteria — to see if they contaminated themselves removing equipment following a simulated patient encounter. The bacteriophages used were Pseudomonas phage phi6, an enveloped virus commonly used to mimic Ebola; and MS2, a non-enveloped virus more like norovirus, and more difficult to remove from the environment than Ebola.
“MS2 is a very conservative surrogate for Ebola,” Casanova said. “It’s much hardier in the environment.”
After completing a standardized task while in PPE, a trained monitor guided them through the doffing process. After doffing, inner gloves, bare hands, face, and scrubs were sampled for the bacteriophage viruses. Among the 12 healthcare workers studied, phage phi6 was detected at very low levels on hands (1: 8%) but not detected on inner gloves, face, or scrubs. Non-enveloped MS2 was detected at low levels on hands (2: 17%), inner gloves (4: 33%), and scrubs (3: 25%), but not on the face.
“Fortunately, hand contamination is relatively rare and when it happens it is at a low level, but it did happen, which is not great,” she said. “We found almost no phi6 and this is true of our larger data set. So, the enveloped virus in theory very [rarely] transferred. That is likely because enveloped viruses that we use are very susceptible to the agents we use for skin and glove sanitizers. Your basic alcohol hand rub works quite well with phi6 and that’s why we saw virtually no transfer. So, for enveloped viruses like Ebola, alcohol hand rubs likely are getting us a long way to where we want to be. For MS2, that is not necessarily the case.”
A particular concern is MS2-contaminated inner gloves worn beneath another, outer pair, she said.
“That suggests that inner gloves are doing what they are supposed to do,” Casanova said. “In this process, you take off your outer gloves, and then it is the inner gloves that are being used to touch most of your PPE items as you remove it. So, really, inner gloves are becoming contaminated instead of your bare hands, but that does reinforce the idea that we have to be careful about how we remove the inner gloves.”
Glove Controversy
This finding recalls a controversy during the 2014 Ebola outbreak. Sean Kaufman, MPH, CHES, CPH, CIC, MBTI — who trained workers in Africa during the 2014 outbreak and oversaw infection control measures for the first two Ebola patients admitted to Emory University in Atlanta — criticized the CDC for its initial recommendations to protect workers.
“The CDC had put out an SOP for healthcare workers that was inappropriate,” says Kaufman, who is now directing a new high-containment infectious disease training program at the Southern Research Facility. “I reached out to CDC while I was in Liberia to tell them, based on what I was seeing, the SOP was inappropriate, saying, ‘This is not something healthcare workers should do — you are going to get people sick.’ The long story short is that I was right.”
The CDC guidelines were in flux when two U.S. nurses in Dallas were infected, but one subsequent change was a recommendation for wearing two pair of gloves instead of one. Press coverage at the time highlighted this change and Kaufman’s concerns.2
HIC recently asked the CDC for a response to Kaufman’s charges that the initial PPE protocol was inadequate for Ebola. Michael Bell, MD, a medical epidemiologist in the CDC division of healthcare quality promotion, sent the following statement:
“The experience with Ebola virus infection in the United States and abroad demonstrated the urgent need for infection control training for all staff in healthcare facilities, and the importance of careful assessment and triage systems,” Bell said in the statement. “In the United States and elsewhere, many different types and combinations of protective equipment have been used safely and successfully, but they all require consistent adherence to correct use, including removal and disposal, by all staff members.”
Though Ebola, as evidenced in the Congo, typically erupts in violent outbreaks and subsides, the outbreak forever altered perceptions of the virus as it devastated West Africa over a prolonged period. Some 11,000 people died before it was over, and the U.S. and other nations saw cases via travelers and returning healthcare workers. According to the WHO, from January 1, 2014 to March 31, 2015, there were 815 confirmed and probable cases of Ebola infection in healthcare workers in Africa. Among the health workers for whom final outcome is known, two-thirds of those infected died, the WHO reports.3 A highly successful vaccine was developed and trialed near the end of the outbreak, and the WHO has thousands of doses if need arises.4
“I respect Ebola as a virus, but what we saw in 2014 was unlike anything we have ever seen with Ebola. It was almost like a 100-year flood,” Kaufman says. “There will be outbreks. This is normal, but these outbreaks are usually contained very easily because of the nature of the virus.”
REFERENCES
- Healthcare Worker Safety/Occupational Health Oral Abstracts 1205. Multicenter Evaluation of Viral Self-Contamination During Doffing of Ebola-Level Personal Protective Equipment (PPE). APIC Conference. Portland. June 14-16 2017
- Guidelines on Ebola Led to Poor Hospital Training, Experts Say. New York Times Oct 15, 2014: http://nyti.ms/2tiDcm7
- WHO. Health worker Ebola infections in Guinea, Liberia and Sierra Leone. A Preliminary Report. 21 May 2015: http://bit.ly/2sXRIwE.
- Henao-Restrepo AM, Camacho A, Longini IM, et al. Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring vaccination, open-label, cluster-randomised trial. Lancet 2017; 389:10068:505–518.
