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Ebola screening: “Mostly a waste of time” note experts

Both governments recently announced similar new measures to prevent the importation of the virus, including temperature screening of certain airline passengers who arrive from the Ebola-affected West African countries of Liberia, Guinea and Sierra Leone.

However, a number of experts are questioning the effectiveness of this kind of screening and whether it will make the public safer.

“Mostly a waste of time,” said Dr. Jay Keystone, senior staff physician at Toronto General Hospital’s tropical disease unit. “This is optics to make the country feel safer.”

“Is this going to help stop Ebola from coming into the country? Highly, highly, highly unlikely.”

In Canada, quarantine officers are being dispatched to airports in Montreal, Toronto, Vancouver, Halifax, Ottawa and Calgary. Travellers coming into one of those airports from one of the affected Ebola areas who are ill or acknowledge that they have been in contact with a sick person will be referred to a quarantine officer who will assess these individuals and take their temperature. (Fever is one of the symptoms of the disease.)

“I think this is designed to make the Canadian population more comfortable when in fact they don’t need to feel more comfortable because we can handle the infection here,” Keystone says. “We may get a case or two or three. We’re not going to have an outbreak or an epidemic.”

“There are people who are freaked out,” Keystone acknowledges. “The problem is there’s a difference between the science of Ebola and the emotional response to Ebola. And what were’ seeing in Canada and the U.S. is the emotional response.”

The U.S. measures are more expansive. Officials will be taking the temperature of all travellers coming into five major U.S. airports from those areas in Western Africa.

“What they’ve done is very different than what Canada did with SARS,” said Lawrence Gostin, a professor at Georgetown University in Washington and faculty director of the O’Neill Institute for National and Global Health Law.

“It’s not mass fever screening. And I was very worried that the U.S. might do that. It’s the most moderate and measured approach the president could take, and he’s under intense political pressure to do more.”

Temperature screenings are hardly foolproof, and pose their own challenges. 

For one, the incubation time for Ebola is between two and 21 days, meaning that those who travel soon after being infected may not exhibit symptoms. Duncan, for example, had his temperature taken three times at the Liberian airport, and all his readings were considered to be within normal levels. Passengers can also take Tylenol to bring down fever symptoms.

Although Gostin favours the current U.S. approach over other possible measures, he agrees that there’s no assurance these measures will be effective.

“You’re going to get people who have a lot of other conditions. A lot of false positives,” said Gostin. “It’s the peak flu season, so they’ll have the flu. Coming from Africa, they’re more likely to have malaria or tuberculosis, which mimics the symptoms of Ebola.”

“We know that [fever] is potentially the first symptom for Ebola,” added Jason Tetro, a microbiologist and author of The Germ Code. “But it also is the first symptom for practically every other infectious disease is out there.”

But while Tetro also expressed doubts about the effectiveness of temperature screening, and whether the method will ever detect someone with Ebola at an airport, he praised Ottawa’s actions.

“The number of people who come from the affected countries is very minimal. So really this is an excellent move to reinforce the public trust.  

“Logistically, it’s a simple move to perform and in terms of actual effectiveness, the reality is there’s such a low likelihood that someone is going to come here [with Ebola] anyways that there’s no harm in doing it.

“If Canadians understand that the government … is essentially giving Canadians the visual cues they need to feel safe, there’s nothing wrong with that.”

Gostin also agreed that that while taking the temperatures of incoming passengers from Ebola-affected countries may not be effective, they are reasonable steps to take.

“You want to know if someone has travelled from a region that has high reservoirs of infection. You want to know if they’ve been near somebody who could have had Ebola and they may be exposed. And you want to see if they have symptoms. I think all those things are reasonable.”