It isn't just about the science.

What Science Can't Tell You About Ebola

Clive Crook is a Bloomberg View columnist and writes editorials on economics, finance and politics. He was chief Washington commentator for the Financial Times, a correspondent and editor for the Economist and a senior editor at the Atlantic. He previously served as an official in the British finance ministry and the Government Economic Service.
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The argument over the risk Ebola poses to the U.S. is getting cast as a disagreement between smart people who trust science and dumb people who panic for no reason. I don't see it that way.

To begin with, I haven't noticed much of the panic and hysteria I keep reading about. Maybe it's confined to Twitter or candidates for public office. More important, this supposed contest between science and ignorance is false. It overstates what science can tell us and insults the intelligence of the great majority of citizens.

Does it make sense to quarantine health workers returning from West Africa, as the governors of New York and New Jersey proposed? The science doesn't support it, experts on the disease have said; we're acting out of an abundance of caution, say the governors. Are the governors just plain wrong? Is this really a battle between reason and fear? No. It's more complicated than that -- and pretending it's simple doesn't help.

To begin with -- how shall I put this? -- the science on Ebola isn't settled. Experts are still working to understand the disease. Methods of transmission seem to be well understood, but not yet completely. Some crucial questions (such as the delay between the onset of symptoms and the contagious stage of the illness) involve probabilities, not certainties.

The protocols for preventing spread of the disease seem to change every few days. In addition, doctors and other health professionals sometimes make mistakes -- and, in the current emergency, mistakes have plainly been made. Given all this, "trust the science" isn't persuasive. In fact, you have to wonder about the scientific aptitude of anybody who would say such a thing.

But here's the main thing. Even if the science told us everything we need to know about Ebola, that wouldn't settle the policy question. An otherwise excellent editorial by Jeffrey Drazen and others in the New England Journal of Medicine criticizes the governors, but in doing so makes this elementary mistake. The article clearly explains that science has "very strong reason" to believe that asymptomatic Ebola is not contagious and explains that field experience backs this up. But then it goes on:

A cynic would say that all these "facts" are derived from observation and that it pays to be 100% safe and to isolate anyone with a remote chance of carrying the virus. What harm can that approach do besides inconveniencing a few health care workers? We strongly disagree. Hundreds of years of experience show that to stop an epidemic of this type requires controlling it at its source. Médecins sans Frontières, the World Health Organization, the U.S. Agency for International Development (USAID), and many other organizations say we need tens of thousands of additional volunteers to control the epidemic. We are far short of that goal, so the need for workers on the ground is great. These responsible, skilled health care workers who are risking their lives to help others are also helping by stemming the epidemic at its source. If we add barriers making it harder for volunteers to return to their community, we are hurting ourselves.

In the end, the calculus is simple, and we think the governors have it wrong.

I accept the doctors' conclusion -- mandatory quarantine is a bad idea -- but not the way they justify it. You don't have to be a cynic, a slanted term, to argue for "better safe than sorry." The calculus isn't simple, either. The crucial thing, though, is that the doctors' sensible conclusion doesn't rest solely on the science.

It requires a delicate judgment about many different risks and costs -- the risk of extra U.S. cases in the short run, the risk of discouraging health workers from traveling to West Africa so that the disease keeps spreading there, the cost in civil liberty of restricting people's movements, and so on. I agree with the doctors about where the balance lies, but the issue isn't easy and, in any event, it isn't just about the science of Ebola.

The doctors conclude, "We should be honoring, not quarantining, health care workers who put their lives at risk..." We should indeed be honoring them -- and, unless I'm mistaken, we are -- but that comment isn't science; it's pure politics. Forgive me for stating what should be obvious, but if the facts about the transmission of Ebola were different, one could imagine that mandatory quarantine would be justified; and if it were, the policy would imply no disrespect to the health professionals involved.

In practical terms, rather than treating people like children and telling them to trust the adults, policy-makers should get into the trade-offs.

Mandatory quarantine for returning health workers is a bad idea? That seems right. The same goes, no doubt, for the "travel ban" (whatever that means) that some have proposed. But some restrictions on unnecessary travel seem both prudent and comparatively painless. And, as the NJEM article says, "At this point, the public does need assurances that returning workers will have their temperatures and health status monitored according to a set, documented protocol." That's an infringement of liberty too -- one that the doctors, for some reason, don't feel they need to justify.

As in many other areas, smart policy starts with the science, but doesn't end with the science. You need some common sense and ordinary good judgment too. Claiming otherwise brings science into disrepute and makes it harder for scientists to play their essential role.

This column does not necessarily reflect the opinion of Bloomberg View's editorial board or Bloomberg LP, its owners and investors.

To contact the author on this story:
Clive Crook at

To contact the editor on this story:
James Gibney at