From security to risk: reframing global health threats

In October 2014, at the height of the west African Ebola outbreak, the Director-General of the World Health Organization (WHO), Margaret Chan, commented: 'In my long career in public health ... I have never seen a health event strike such fear and terror, well beyond the affected countries.' 1 The widespread sense of being at risk was remarkable because the likelihood of infection was very low.As Chan commented elsewhere: 'Experience tells us that Ebola outbreaks can be contained, even without a vaccine or cure.' 2 Although the disease had a high mortality rate, its transmission vector-mostly via bodily fluids-made it relatively difficult for individuals to become infected.Thus when the Scottish nurse Pauline Cafferkey flew from London to Glasgow while infected with the disease, no other passenger on that flight became infected as a result.Nevertheless, concern over this incident prompted the UK Department of Health (DoH) to issue no fewer than nine tweets on 29 December 2014, when the news of Cafferkey's infection was made public, in an attempt to reassure the public. 3 This was a much more intense burst than any previous Twitter activity from the DoH concerning Ebola; 4 and one of those 29 December tweets was retweeted four times more than the next most popular tweet.This tension between feeling 'at risk' and the low likelihood of infection was, we suggest, not a case of misperception of the level of risk, which had it been better communicated would have reduced society's fear, 5 but rather reflected a broader shift in society's understanding of risk, of which health threats form part.Assessments surrounding the increased risk of, and from, outbreaks of diseases such as Ebola have been a key feature in the rise of global health on both academic