Screening for Ebola

Summary

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More or Less: Screening for Ebola

BBC Radio 4, October 25, 2014
Host: Ruth Alexander
Featured Contributors: Dr. Cameron Khan, Ben Carter, Professor David Mabie

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Episode Overview

This episode investigates the effectiveness and practicality of airport screening measures introduced during the 2014 Ebola crisis. Host Ruth Alexander leads a fact-driven discussion with expert guests, exploring whether such measures actually increase public safety, unpacks notable statistics and case studies, and scrutinizes both government and private sector contributions to the global Ebola response.

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Key Discussion Points & Insights

1. The Logic and Logistics of Ebola Screening

• Screening Methods:

  • Three main traveler screening strategies for Ebola-exposed countries (Liberia, Sierra Leone, Guinea) are explored:

    • Exit screening at departures from only three main cities (the capitals).
    • Entry screening at 15 entry points for direct flights into other countries.
    • Widespread entry screening at ~1,200 airports worldwide, affecting around 362 million travelers, due to lack of direct flights and the challenge of identifying connecting passengers.

  • Most passengers subjected to these wider screenings would have no connection to affected regions (99.9%).

    “If you want to identify individuals who had originated in West Africa … about 99.9% of the travelers that would be screened would not actually have even originated from West Africa.”
    – Dr. Cameron Khan [01:47]

2. Limits of Screening Effectiveness

• Incubation Period vs. Flight Duration:

  • Ebola’s average incubation is nine days; typical flight duration is about six hours. Thus, very few would become symptomatic during a flight.

  • Notable cases (e.g., Dr. Craig Spencer, Thomas Eric Duncan) illustrate that screening at airports failed to catch infected individuals, as symptoms developed after landing.

    “The window for symptoms to develop on board the plane is really small.”
    – Ben Carter [02:55]

• Probability of Infectious Travelers:

  • Of all travelers from affected countries, only about 2.8 per month would likely be infected due to low prevalence and limited travel.

    “Only 2.8 travelers on average each month... the risk is there, but it's very small.”
    – Ben Carter [03:52]

3. Lessons from Historical Screening Attempts

• The SARS Example (Canada, 2003):

  • One million screened (via questionnaires and thermal scanners); not a single SARS case found.

  • Cost: 17 million Canadian dollars.

    “Overall, of all those more than a million people screened, not one case of SARS was found.”
    – Professor David Mabie [05:31]

• When Screening Did Matter (Nigeria, 2014):

  • An ill man arriving from Liberia collapsed before screening was instituted, later confirmed with Ebola. Nearly 900 contacts were tracked—a number that could have been much higher had he entered the city.

    “Had he not collapsed at the airport... the number of contacts would have risen rapidly.”
    – Ruth Alexander [05:53]

4. Who’s Funding the Ebola Response?

• Comparing National and Corporate Giving:

  • Headline: “Spain, Norway and Luxembourg donate less to battle Ebola than IKEA.”

  • IKEA was credited with a $6.8 million donation; the three countries together, $3.9 million (at one point).

  • Norway disputed its figure, claiming actual pledges totaling $50 million, though not all funds ran through UN channels and thus did not appear on public trackers.

    “That's three rich countries outspent by a furniture shop.”
    – Ruth Alexander [06:45]

    “IKEA has lots of shops, but they are owned by a charity... it does help IKEA avoid a lot of tax.”
    – Ben Carter [08:08]

• Charitable Foundations and Generosity:

  • IKEA’s foundation, while large in assets, has been called the “richest in the world, but also one of the least generous.”

    “Those are The Economist's words, Ruth, and not ours.”
    – Ben Carter [08:46]

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Notable Quotes & Memorable Moments

• Effectiveness of Mass Screening:

  “Of all those more than a million people screened, not one case of SARS was found. The cost of this exercise was 17 million Canadian dollars.”
  – Professor David Mabie [05:36]

• Real-world Impact of Missed Screening:

  “Had he not collapsed at the airport and got into the center of Lagos... the number of contacts would have risen rapidly.”
  – Ruth Alexander [05:53]

• Ebola Aid Funding Headline:

  “Spain, Norway and Luxembourg donate less to battle Ebola than IKEA. So that's three rich countries outspent by a furniture shop.”
  – Ruth Alexander [06:45]

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Timestamps for Important Segments

| MM:SS | Topic | |-------|----------------------------------------------------------------------------------------| | 00:18 | Introduction to Ebola screening and global government responses | | 01:14 | Dr. Cameron Khan on screening strategies and numbers | | 02:50 | Ben Carter on incubation periods and weaknesses of airport screening | | 03:52 | Probability of infected travelers and scope of risk | | 04:58 | Professor David Mabie: Lessons from SARS and effectiveness of screening | | 05:43 | Example of missed screening and outbreak potential in Nigeria | | 06:38 | Discussion on financial aid—comparing nations and IKEA | | 07:36 | Clarification on Norway’s donations and limitations of public donation figures | | 08:05 | Examination of IKEA’s corporate and charitable structure relating to its donations | | 08:46 | Economist’s critique of IKEA’s charitable giving |

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Summary

This episode of More or Less offers a clear-eyed statistical analysis of airport Ebola screening policies, exposing both their limited effectiveness and the significant logistical hurdles involved. The discussion is enriched with historical perspective (SARS, Nigeria) and clever analysis of financial aid coverage, notably highlighting the influence and limitations of both government and large corporate donors. The tone remains factual, lightly skeptical, and ready to debunk headline misrepresentations surrounding both health policy and charity.

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Transcript

[Ruth Alexander]

This is the short edition of More or Less, first broadcast on the BBC World Service.

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[Ruth Alexander]

hello, this is More or Less on the BBC World Service, and I'm Ruth Alexander. As governments around the world consider ways to ensure that their countries don't succumb to an outbreak of the Ebola virus, some have introduced mandatory airports screenings for passengers arriving on flights from those West African countries that have been affected. Airports in the United States, Canada, United Kingdom, France and the Czech Republic are taking temperatures and giving health questionnaires to people arriving from Liberia, Sierra Leone and Guinea. But how effective is this type of screening, and will it make the public safer? We've been speaking to Dr. Cameron Khan, an infectious disease physician at St. Michael's Hospital in Toronto, Canada. He's also one of the authors of a paper that examined the potential of the Ebola virus to spread across international borders via commercial air travel. In the first part of his study, he wanted to know how efficient screening of travelers is.

[Dr. Cameron Khan]

When countries are looking at whether or not they should be performing screening of travelers, there are really three options. The first is what we call exit screening. This is screening of travelers as they are leaving Guinea, Liberia and Sierra Leone. And it turns out that there are only three points at which you would need to screen travelers. Those are the capital cities of each of the respective countries. The other option is to screen travelers on direct flights that are leaving the affected countries. And in that instance, you'd be screening the same travelers. It's just now that you'd be screening them at the point of entry, which happens to be in 15 cities across 15 different countries. And finally, the other option, which is relevant for most of the world, is that there are no direct flights coming from those three countries, in which case you'd have to screen in about 1200 different airports and screen roughly 362 million travelers. And that's because since there are no direct flights, you'd have to be screening travelers coming through connecting flights. Essentially, any city would have to screen all international travelers in order to be able to identify individuals who had originated in West Africa. About 99.9% of the travelers that would be screened would not actually have even originated from West Africa.

[Ruth Alexander]

And as Dr. Kahn explained, people leaving those countries are being screened at point of departure, assuming that those passengers who do show symptoms prior to boarding are refused permission to fly. The entry level screening can only identify Those people who develop symptoms while flying, what are the chances of that happening? Ben Carter's been looking at this.

[Ben Carter]

Hi, Ruth. First we need to point out that the incubation period for Ebola, that's the time from exposure to the virus to a person showing symptoms, is on average about nine days. Then we factor in that the average flight out of one of the affected West African countries is around six hours. So the window for symptoms to develop on board the plane is really small. And Dr. Craig Spencer, the doctor who tested positive for Ebola in New York on October 23, was screened at JFK Airport on his return from guinea on October 17. But he wasn't picked up because he wasn't showing symptoms at the time. Even if screening had already been in place in the United States, Thomas Eric Duncan, the first man to be diagnosed in the current outbreak, wouldn't have been picked up either, because he only developed symptoms a week after he was back on US soil.

[Ruth Alexander]

And there was another question that Dr. Kahn and his team wanted to find an answer to. How many of those infected with Ebola in those three countries were likely to fly?

[Ben Carter]

And again, that number was low. Only 2.8 travelers on average each month. That's because even in the countries at the center of the Ebola outbreak, the chances of someone being infected is actually quite low. And a relatively small number of people in these countries fly anyway. The risk is there, but it's very small.

[Ruth Alexander]

Governments have known for quite some time that identifying passengers carrying infectious diseases is a difficult task because they've tried it before. In 2003, an outbreak of SARS, severe acute respiratory syndrome, began in the Guangdong province in China. In the following months, cases were reported in Hong Kong, Singapore, and Vietnam. The World Health Organization issued a global health alert for SARS as it became clear that the disease was being spread by global air travel. We've been talking to David Mabie, professor of communicable diseases at the London School of Hygiene and Tropical Medicine and co author of a British medical journal paper, Airport Screening for Ebola. Professor Mabie looked at data from Canada, which introduced airport screening during the SARS epidemic.

[David Mabie]

700,000 people filled in a questionnaire, of whom about two and a half thousand answered yes to at least one of the questions. Those people all referred for medical investigation, and none of them had sars. At the same time, at those major airports, they introduced thermal scanners, which are supposed to detect people with a raised temperature. And almost half a million people went through those scanners, of whom 95 were thought to have a raised temperature and were referred to a nurse who checked what their temperature really was and actually none of them had a fever. Overall, of all those more than a million people screened, not one case of SARS was found. The cost of this exercise was 17 million Canadian dollars.

[Ruth Alexander]

David Mabie. The dangers of not doing any screening at all at airports, though, can be highlighted by a story from Nigeria. On July 20, a man who was ill flew from Liberia to Lagos. Before exit screening was introduced, he collapsed at the Nigerian airport and was taken to hospital. Three days later, it was confirmed that he had Ebola. Medical experts linked 898 contacts to him, primary, secondary and tertiary. Had he not collapsed at the airport and got into the centre of Lagos, a city with a population of over 20 million people, the number of contacts would have risen rapidly. You're listening to More or Less on the BBC World Service. I'm Ruth Alexander. The United nations have appealed for nearly $2 billion in funding to tackle the Ebola crisis. Some governments have rallied to the cause, but others not so much.

[Ben Carter]

And Ruth, this was summed up by a headline in the British newspaper the Daily Telegraph last weekend.

[Ruth Alexander]

Spain, Norway and Luxembourg donate less to battle Ebola than ikea. So that's three rich countries outspent by a furniture shop. I know IKEA is a big shop with stores in 37 countries, but it is still just a shop. Can this really be true then?

[Ben Carter]

Well, kind of. The article claimed that according to the United Nations Office for the Coordination of Humanitarian affairs, aid tracker Ikea had contributed $6.8 million, while Spain, Norway and Luxembourg had offered just $3.9 million between them. But we need to point out that the aid tracker is updated daily, so the figures have changed since the Telegraph ran their story. Nonetheless, Luxembourg and Spain admit the figures quoted reflected their financial contribution at that time, although they have upped their donations since.

[Ruth Alexander]

Good.

[Ben Carter]

That's right. Norway and the Telegraph did point this out. Disagreed with the figure attributed to them and they've told me that they have pledged $50 million, but only a fraction of that will be channelled through the UN and therefore the majority of it won't show up on Aid Tracker.

[Ruth Alexander]

And what about Ikea's donation? A not insignificant sum for a shop.

[Ben Carter]

Well, it's not. And nobody would dispute that contributing nearly $7 million to help Takala Bola is a bad thing.

[Ruth Alexander]

There's a book coming, isn't there?

[Ben Carter]

Well, there always is. IKEA have lots of shops, but they are owned by a charity, the Stichting Incker foundation, which was set up in the Netherlands as a non profit making entity dedicated to innovation in the field of architectural and interior design. That might sound like a strange corporate structure, but it does help Ikea avoid a lot of tax the foundation gave 101 million euros to charitable causes last year, but it's estimated to hold assets worth more than 30 billion euros. Perhaps it's not surprising that in 2006 the Economist magazine said that the foundation was the richest in the world, but also one of the least generous. And those are the Economist's words, Ruth, and not ours.

[Ruth Alexander]

Alright, thanks Ben. Well, that's all we have time for this week. If you have any numbers you want investigating, please do email us at more or lessbc.co.uk you can listen to other editions of More or Less at our website where we explore subjects from the chances of someone running a sub 2 hour marathon to whether species populations have dropped by half in the past 40 years. To do that by going to our website bbcworldservice.com online more or less

[Ben Carter]

There

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