Perspective: The mutable message on Ebola mutation
By Gary Evans, Executive Editor
The idea that the Ebola virus may mutate and become transmissible through the air continues to be pushed to the margins of the public health discussion, now all but relegated to the nightmares of a panicked public.
Thus it seems the Centers for Disease Control and Prevention was merely following suit with recent issuance of a fact sheet entitled "Why Ebola is Not Likely to Become Airborne". (http://www.cdc.gov/vhf/ebola/pdf/mutations.pdf)
"Even as Ebola mutates, like all viruses do, it would be very unusual for it to change how it is transmitted, especially when it is spreading easily through a population," the CDC states. "Over the course of millions of years, viruses do sometimes mutate to change how they spread infection. For Ebola, this would require multiple mutations in the virus over a very long period of time."
That conclusion seems rational and scientific enough, reframing Ebola as a virus that spreads primarily by direct contact. Reassurance is a welcome sight after the reign of fear that followed the three-case Ebola outbreak in Dallas. That said, the inconvenient truth is that the threat of mutation was very much a part of the early public health narrative as it became clear the virus was overwhelming containment efforts in West Africa.
Margaret Chan, MD, director of the World Health Organization, warned in an Aug. 1, 2014 speech that "constant mutation and adaptation are the survival mechanisms of viruses and other microbes. We must not give this virus opportunities to deliver more surprises." Similarly, CDC Director Tom Frieden, MD, said at a Sept. 2 press conference, "[Mutation] risk may be very low, but it’s probably not zero. The longer it spreads, the higher the risk."
Even President Obama weighed in on the risk of mutation on Sept 7, resulting in headlines like "Obama Warns Ebola Virus Could Mutate If Outbreak Is Not Controlled."1 "We have to mobilize the international community, get resources in there . If we don’t make that effort now, and this spreads not just through Africa but other parts of the world, there’s the prospect then that the virus mutates," the president said. "It becomes more easily transmittable. And then it could be a serious danger to the United States."
Obama was no doubt briefed by public health advisors on that point, and the mention of mobilizing the global community to action sheds light on the motive for the message. Indeed, since the CDC and WHO have been aware of Ebola since the first outbreak almost four decades ago, is it really likely that they came to such dramatic new insights about the risk of mutation during this early time period in the ongoing epidemic?
True, they were looking at an outbreak that is still setting records for duration and case counts, but it is tempting to conclude that the CDC and others were citing this mutation threat primarily to create a sense of urgency and spur a global response. However, the fine line between urgency and near panic was close to being crossed after some independent researchers and scientists began openly discussing the mutation threat. A New York Times op-ed by well-known epidemiologist Michael Osterholm, PhD, warned if mutation created airborne Ebola it "could spread quickly to every part of the globe, as the H1N1 influenza virus did in 2009, after its birth in Mexico."2 Similarly, David Sanders, PhD, an associate professor of biological sciences at Purdue University in Lafayette, IN warned, "It’s not something to be dismissed. I can’t put a number on it, but I can tell you it’s a non-zero number."3
There was unease and pushback as such mutation warnings were amplified. As a result, the recent CDC fact sheet notes: "Since discovered, Ebola has proven to be a stable virus with a relatively constant mutation rate. The Ebola virus samples from this outbreak are 97% similar to the virus that first emerged in 1976. Scientists monitoring the virus have not seen any evidence to suggest that the Ebola virus may be mutating to become more contagious or more easily spread."
This was actually one of the early reassuring messages when the outbreak first began, but it may have morphed into the mutation threat as calls were being made for more countries to step up and assist in eradicating the epidemic in Africa. Perhaps only the prospect of the virus getting into their own countries possibly through mutation that enhanced transmission — could stir the nations of the world to action. If so, it worked. Today many global organizations and nations from European countries like the United Kingdom, France and Germany to Asian nations China and Japan have provided assistance or donated considerable sums of money to help fight Ebola in Africa. As of Dec. 17, 2014 there were 18,569 Ebola cases and 6,900 deaths in the African outbreak.
- 1.CBSDC/AP. Sept. 7, 2014:
- Osterholm, M. What We’re Afraid to Say About Ebola. NY Times, Sept 11, 2014: http://nyti.ms/1wl0x14
- Livingston, M. Ebola virus could spread by air. Layfette Jrl & Courier Oct 8, 2014: http://on.jconline.com/1uYfy8K