Wednesday, 18 March 2015

Catching Ebola: mistakes, messages and madness [amended]

Written by Dr. Ian M. Mackay and Dr. Katherine E. Arden

Despite obvious community and media fear, speculation and exclamation that Ebola virus would enter and spread widely within countries outside the hotzone, such an event did not come to pass in 2014. The early public health messaging on Ebola virus and disease were, for the most part, spot on. 

In 2014 and 2015, thousands of cases of Ebola virus disease (EVD) ravaged Guinea, Sierra Leone and Liberia in 2014 (the "hotzone"). A smaller outbreak was defeated in Nigeria [8] and another distinct Ebola virus variant drove an outbreak of EVD in the Democratic Republic of the Congo[7] - they too controlled spread of the virus. Ebola virus travelled from the hotzone to other countries including Senegal, Nigeria, the United States of America (USA), Mali and most recently, the United Kingdom. It did this by hitching a ride in a usually unknowingly infected human host. 

Over 40 people have been intentionally evacuated or repatriated for observation or more aggressive supportive care - and perhaps the use of experimental therapies - to France, the USA, Spain, Sweden, Norway, Denmark, Germany, Netherlands, Italy, Switzerland and the United Kingdom.[1,18] 

Recently, the last country outside of Africa to have unintentionally acquired a case of EVD, the United Kingdom, passed a milestone; 42 days since the last ill patient tested negative for Ebola virus. They were declared free of known virus transmission.[17]

Containing the spread of each imported case has relied upon stringent infection prevention and control measures and the identification and monitoring of each and every contact of an Ebola virus infected person. And these have been used with great success. No country, apart from the three in which transmission has been widespread and intense, has seen the appearance of multiple and continuing rounds of new EVD cases. A rough calculation of the numbers of contacts falling ill from each EVD index case who travelled outside the hotzone is shown in the table. It only includes those with data available publicly.

On average, fewer than 1 in 100 contacts (0.8%) came down with EVD. Not the easiest virus to catch? If you compare that to measles, 9 in 10 non-immune people close to an infectious measles case will acquire disease (90%).[19]

Table 1. Index cases and the proportion of contacts they infected
a-man travelled overland from Guinea while infected; b-man with EVD repatriated from Liberia; c-man who flew while symptomatic to Lagos, Nigeria with a stopover in Lome, Togo; d-man flew from Liberia while infected; e-male healthcare worker returned from Guinea; f-a 2 year old girl travelling overland while infected; g-male travelled by car to a clinic in Bamako, Mali from Guinea (assumed Ebola case); h-female healthcare worker returning from deployment in Sierra Leone; i-this figure may indicate all contacts for  both Mali cases
The extent of the fear inspired by the first imported EVD case was especially clear from the massive spike in social media content from the United States which followed the arrival from Liberia of an individual with EVD; far more social media activity than had been seen in the United States to that point, or since.[14,10] This month, even though 11 contacts/associates are being flown back to the United States for observation; on the heels of the index case, social media activity has barely responded – in fact Twitter is possibly more positive/neutral about Ebola in the US in March 2015 than in August 2014, rather than excessively fearful, mean or just plain hysterical.[10] 

Some of the heat may have been taken out of the emotional response to Ebola outside Africa because it is now clear that a catastrophic pandemic is not going to happen. Kinda like we were told. I know; it;s so uncool to be reminded that you were told something by a grown up - and it was right! 


Nations with better (some!) healthcare infrastructure, preparedness, healthcare to patient ratios and those who got advice and help quickly, curtailed the spread of EVD. Kicked it out. Stomped on it. Terminated it. This was true even when contacts had been classified as at high risk of getting sick.[15] 

Public health messaging made some big calls early on. Some examples include tweets by Head of Public Relations for the WHO, Gregory Härtl, and later by the Centers for Disease Control and Prevention’s Director, Dr Tom Freiden.[11] They made it clear that Ebola virus was not easy to catch and that measures to stop an outbreak were known.[16] At the time, this didn't jibe with other voices and the unprecedented number of EVD cases and deaths, especially from August onwards, that were tallying up at an exponential rate in west Africa. But those messages, while technically correct, probably didn't convey enough of some of the biggest factors in a disease outbreak - fear, ignorance (meant only in the sense of no specific knowledge of Ebola virus and EVD), tradition and history - the human factors rather than the viral ones. Some comments about transmission suggested essentially no chance of even a single new case happening on the home soil of richer countries - they were overly enthusiastic. They were unjustifiable and when some hospital workers in non-African countries became infected, they were ultimately seen for the mistake in message crafting that they were.

Much of the science of the Ebola epidemic is yet to be written, but what we know today is that it is unlikely that Ebola transmission is any different from what was observed decades ago. Direct, physical contact with a very ill person’s fluids is the overwhelmingly biggest risk factor to target in reducing disease spread. And even then there's no guarantee that disease will result from all instances of contact. We still have much to learn.

What has changed since the bad old days? We’ve learned how to better manage and support EVD cases. EVD is a disease that caught us a little unawares in its combination of "skills" - it spreads by care and through direct contact, accrues a lot of virus in the blood but also vast quantities in explosively propelled fluids produced from "both ends"; virus that remains infectious for even longer in urine and semen than in blood. Quite the mix of issues to deal with.

EVD is no longer a death sentence, and this needs to become part of the new messaging paradigm. It's a message that may still be highly relevant to those in Guinea and Sierra Leone who seemingly would still rather risk death than seek care at a treatment unit. Post-mortem detection of EVD cases is ongoing, although may be on the decrease but also nearly a third of cases in Guinea and Sierra Leone are arising from unknown human sources.[21] Contextual communication is needed from within each country and region. That aspect cannot be allowed to wane. 

With early care, and active care, rather than the palliative model that seemed to occur when the ratio of EVD cases to healthcare workers was too high, patients mostly surviveThe EVD treatment center at the Hastings Police Training School near Freetown, Sierra Leone stands as a model for successful life saving and is the best described example of this from the west Africa epidemic to date.[20]

Ebola virus infection is not easy to catch, it can be survived much more often than was generally accepted and its spread can indeed be stopped. Stopping an Ebola outbreak quickly seems to be helped mostly by prior education, ongoing communication, forewarning and preparation but also needs ongoing surveillance, functional healthcare infrastructure, a range of experienced workers and all of that must all be under-written by money.

But even with all that help in place, mistakes will be made and lessons will be learned, by everyone, all the time. Embrace that. We're all human.