The World Health Organization (WHO) is poised to begin vaccinating healthcare workers with an experimental new Ebola vaccine, but continues to hold off as an outbreak in the Democratic Republic of the Congo appeared to be dissipating as this report was filed.

As of June 19, 2017, there have been five confirmed and three probable cases of Ebola in the Congo, the WHO reported.1 Additionally, there have been 99 suspected cases reported that tested negative on lab follow-up. The last confirmed case was diagnosed on May 17, 2017. Of the eight confirmed and probable cases, four people survived. The confirmed and probable cases were reported from Nambwa (four confirmed and two probable), Ngayi (one probable), and Mabongo (one confirmed).

“Data modeling suggests that the risk of further cases is currently low but not negligible, and decreases with each day without new confirmed/probable cases,” the WHO reported. “As of the reporting date, 97% of simulated scenarios predict no further cases in the next 30 days.”

The cluster of cases and deaths were first reported as an unidentified illness in late April 2017. The affected area is remote and hard to reach, with limited communication and transport infrastructure, the WHO noted. Fruit bats are thought to be a natural reservoir for Ebola, and were implicated as the source of the 2014 outbreak.

Though Ebola typically erupts in violent outbreaks and subsides, that 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 Jan. 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.2

A highly successful vaccine was developed and trialed near the end of the outbreak, and the WHO has thousands of doses if the need arises.3 In a tactic similar to the one used to eradicate smallpox, WHO is considering vaccinating a “ring” of case contacts and people around the affected area.

“The protocol for a possible ring vaccination has been formally approved by the national regulatory authority and Ethics Review Board of the Democratic Republic of the Congo,” WHO reports.4 “The government [of Congo] with support of WHO and other partners are working on detailed planning and readiness to offer access to the … experimental/investigational vaccine, within the expanded access framework, with informed consent and in compliance with good clinical practice. Planning and readiness should be completed urgently to be able to rapidly initiate ring vaccination should an Ebola laboratory-confirmed case be identified outside already-defined chains of transmission. The vaccine would be offered to contacts and contacts of contacts of a confirmed Ebola case, including healthcare workers and field laboratory workers.”

A 100-year Flood

With a vaccine now available and the hard lessons learned from the 2014 outbreak, an infectious disease expert and PPE trainer thinks the hemorrhagic virus will be contained.

“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,” says Sean Kaufman, MPH, CHES, CPH, CIC, MBTI, who is directing a new high-containment infectious disease training program at Southern Research in Birmingham, AL. “There will be outbreaks. This is normal, but these outbreaks are usually contained very easily because of the nature of the virus. I am more concerned with [the next] influenza pandemic, where you are looking at very high levels of morbidity and mortality, unlike anything we have seen.”

Indeed, the general perception that the 2009 H1N1 influenza A pandemic was a relatively mild event could allow a complacency to set in. Yet, one study5 estimated that between 151,700 and 575,400 people died worldwide in the 2009 pandemic. Though many deaths and certainly infections went uncounted, some experts estimate that as many as 1 billion people acquired the virus as it circled the globe. The mortality rate was low by pandemic standards, but there were similar features of past outbreaks such as infection in young, healthy populations. A more virulent pandemic strain resulting after another “antigenic shift” in mutating flu viruses would imperil front-line healthcare workers until a vaccine was developed. Healthcare workers have been among the victims of large respiratory outbreaks of SARS in 2003 and still-percolating MERS.

These cases show healthcare workers are left vulnerable by infection control measures primarily designed to protect patients, emphasizes Kaufman, who advocates a “clinical containment” approach that combines infection control and biosafety techniques that have worked so effectively in labs.

“We had seven Ebola cases come to the U.S. and two nurses got sick,” says. “We have never had a lab worker in the U.S. get sick with Ebola, even though we have worked with it for many years.”

Kaufman — 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 — controversially criticized the CDC for its initial recommendations to protect workers.6

“The CDC had put out a SOP for healthcare workers that was inappropriate,” Kaufman tells HEH. “I reached out to CDC while I was in Liberia to tell them, based on what I was seeing, the SOP was inappropriate: ‘This is not something healthcare workers should do — you are going to get people sick.’ The long story short is that I was right.”

Double Down on Gloves

The CDC guidelines were in flux when the nurses in Dallas were infected, but one subsequent change was a recommendation for wearing two pairs of gloves instead of one. Press coverage highlighted this change and Kaufman’s concerns, and subsequent research suggests the inner pair of gloves may be a critical addition.

A researcher presenting a study on PPE removal recently in Portland at the annual meeting of the Association for Professionals in Infection Control and Epidemiology said inner gloves were contaminated in some experiments using surrogate markers for Ebola.

“That suggests that inner gloves are doing what they are supposed to do,” said Lisa Casanova, PhD, an assistant professor at Georgia State University in Atlanta. “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.”

HEH recently asked the CDC for a response to Kaufmann’s charges that initial PPE protocol was inadequate for Ebola, and received the following response via email from Michael Bell, MD, a medical epidemiologist in the CDC’s Division of Healthcare Quality Promotion:

“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.”

Even if the current outbreak of Ebola is contained, it is good to revisit these issues and evaluate the response in light of future emerging pathogens, Casanova says.

“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,” she said. “Also, a lot of the lessons we are learning about PPE, I think, are transferable to the ordinary healthcare setting. Also, the approach of understanding how well we are doing [with PPE] is transferable.”

REFERENCES

  1. WHO. Ebola Virus Disease. Democratic Republic of the Congo. External Situation Report 25. 19 June 2017: http://bit.ly/2rUUEIZ.
  2. WHO. Health worker Ebola infections in Guinea, Liberia and Sierra Leone: A Preliminary Report. 21 May 2015: http://bit.ly/2sXRIwE.
  3. 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.
  4. WHO. Ebola Virus Disease. Democratic Republic of the Congo. External Situation Report 21. 05 June 2017: http://bit.ly/2s433O8.
  5. Dawood FS, Luliano AD, Reed C, et al. Estimated global mortality associated with the first 12 months of 2009 pandemic influenza A H1N1 virus circulation: a modelling study. Lancet Infect Dis 2012;12:9:687–695.
  6. McNeil DG. Lax U.S. Guidelines on Ebola Led to Poor Hospital Training, Experts Say. New York Times Oct 15, 2014: http://nyti.ms/2tiDcm7.