At the beginning of June, my travel companion and I were lost somewhere in the bowels of the Seoul subway in South Korea. As we puzzled over a map we could barely read, a kind young woman, a surgical mask covering her nose and mouth, stopped and offered to help us find our way. As she led us to our next train, she looked at me seriously. “You should get one of these,” she said, gesturing to her mask. “For MERS.”
Over the next few days, it became hard not to notice the face masks. Many people in South Korea and elsewhere wear masks when they have a cold or allergies, or to filter out air pollution. In some places, it’s even a form of fashion. But the numbers I saw were far beyond those of the occasional cold or cool kid. By the time I left Seoul on June 11, a mask covered 1 out of every 10 faces I saw.
The South Korea outbreak of Middle East respiratory syndrome, or MERS, is the largest yet seen outside the Middle East. As of June 28, 182 people have been diagnosed and 32 people have died. Over the course of the outbreak, more than 15,000 people have been quarantined, including an entire town, forcibly isolated for a single case of the disease.
Despite these scary numbers, the average person walking on the streets of Seoul probably doesn’t need to wear a mask to prevent infection with MERS. The majority of patients acquired infections in hospitals and clinics. Those who did not were in close contact with an infected family member. And even in those close quarters, a basic paper mask may not be effective. “The usual surgical face mask will make sure your own bugs stay inside, but it doesn’t protect you from bugs on the outside,” explains Eskild Petersen, an infectious disease expert at Aarhus University Hospital in Denmark. If you don’t have symptoms of illness, a mask is probably just a fashion statement.
But when people don’t know what to believe and don’t trust the information they are hearing, it’s no wonder they want to do what they can to protect themselves. When it comes to diseases such as MERS, risk communication is not just about handing around the numbers of infected and quarantined. It’s also about admitting when you don’t have all the answers.
Risks fall into different dimensions depending on how much control we feel we have over them and how well we think we know them, says Lisa Schwartz, who studies risk communication at Dartmouth College. Most Americans have a far greater likelihood of getting in a car accident than they do of getting caught in a nuclear meltdown, for example. But most people feel they are in control of whether they get in a car. They don’t have any way to control the local nuclear power plant, and so rate the risk as much higher. Nuclear disasters are also far more likely to make national or international media than the plethora of car accidents that take place every day, looming large in people’s minds despite their relative rarity.
In this way, diseases such as MERS are more like nuclear disasters than car accidents. “It’s something you can’t see — the person next to you could be infected and you don’t know,” says Steven Woloshin, who also studies risk communication at Dartmouth. Tests have confirmed that the MERS virus has not mutated to become more contagious since its arrival in South Korea. But the cases and deaths dominate the national news (often broadcast on televisions in trains across the country), and citizens may feel they have no control over whether they might get exposed to the virus.
These worries may be compounded by the fact that a person’s actual risk of contracting a disease is a tough thing to calculate. The number that epidemiologists stand by is called R0 or “R nought.” This is the measure of how infective a disease is, or how many people one infected person will pass it on to in the course of their illness.
Previous studies of MERS outbreaks in early 2014 estimated the infective potential at between 2 and 6.7 in Saudi Arabia, similar to the numbers for severe acute respiratory syndrome, or SARS, which has an infective potential of between 2 and 4. The World Health Organization states that with such relatively low infection numbers (especially when compared to diseases such as measles, where a single case spawns between 12 and 18 new cases), MERS does not have the infective potential to really become a pandemic. “Based on experience in Saudi Arabia we know that this virus is not generally very infective, except in close conditions such as hospital waiting rooms,” Petersen says.
So, while the average person on the street in Seoul probably faces a very low risk of catching MERS, it’s not a good idea to express too much confidence early in an outbreak. After all, Petersen notes, “you are trying to predict the future.”
Unfortunately, appearing overly confident is where risk messages can break down. “People want to know what the facts are so they can decide what risks they want to take,” explains Baruch Fischhoff, a decision scientist at Carnegie Mellon University in Pittsburgh. Many officials want to put messages out that reassure the public and prevent panic, he says. But those reassurances can backfire. “If you claim greater certainty than you’ve got, and you guess wrong, you’ve blown some of your credibility.”
To many people, admitting uncertainty may sound like a recipe for disaster. Fischhoff says that, in fact, the opposite is true. “I think the record shows people do remarkably well [at assessing risk] if they’re given half a chance, if a good job is done of trustworthy sources communicating the facts.” But if authorities behave in a way that appears untrustworthy, people will be forced to calculate risk based on the little information they trust.
So when communicating about risks — whether it’s an ongoing MERS outbreak, the Disneyland measles outbreak, or bird flu — a trustworthy communicator is just as important as the disease facts themselves. Building trust may mean being open and honest about what communicators don’t know, as well as what they do. “It’s important for people to explain who is at higher risk and who needs to be concerned, and what actions they could take,” Schwartz says. Communicators “need to reassure and be honest, but also explain that there will be more information, and we will learn as we go.”