Illustration: Sarah Grillo/Axios

When it comes to a major infectious disease outbreak, what you don't know very much can hurt you.

The big picture: There is always uncertainty around a new disease. But by failing to quickly ramp up testing for the novel coronavirus, the U.S. has unnecessarily added to that uncertainty — the last thing you want to do in any rapidly evolving challenge.

Why it matters: Right now officials at every level of the U.S. government face agonizing choices about whether to cancel mass gatherings, require workers to telecommute, or even close schools. Those choices will have enormous social and economic ramifications.

  • It's difficult enough to make those decisions if officials have an ideal picture of COVID-19's spread. But by failing to rapidly scale up testing, we've added an additional — and unnecessary — layer of uncertainty to the response to what WHO is now calling a pandemic.

Background: As recently as the 1918 influenza pandemic, scientists were largely in the dark about how a new outbreak spreads.

  • Doctors in 1918 couldn't see the flu virus ravaging the world, and couldn't test people with mild symptoms to get ahead of the outbreak, as Gina Kolata wrote for the New York Times.
  • The inability to rapidly contact trace infected patients meant that containment — as countries including the U.S. are still trying to do with COVID-19 — was largely impossible.

Today scientists can sequence a virus in days, develop rapid tests that can determine infection before obvious symptoms, and use complex mathematical models to predict future spread. But that doesn't mean we know everything about COVID-19, as my Axios colleague Eileen Drage O'Reilly wrote.

  • We still don't know the likely fatality rate of the virus.
  • We don't know exactly how contagious the virus is, or the precise role that children — who seem outwardly unaffected by the disease — may play in transmission.
  • We don't know whether the outbreak will naturally slow down when the weather warms, as tends to happen with influenza.

Be smart: It is these known unknowns that make COVID-19 so risky. It might turn out that COVID-19 kills no more people than the flu, but while we know how the flu spreads and how dangerous it is, we lack the same certainty about the novel coronavirus.

  • That's one reason why, as Harvard epidemiologist Michael Mina put it on a panel last week, this is "the most daunting virus that we’ve contended with in half a century or more."
  • Health officials are facing the epidemiological equivalent of the "fog of war." The faster scientists can get and process data from affected countries, the faster that picture will clarify.

That's why the apparent failure to ramp up testing in the U.S. for COVID-19 is so damaging.

  • It's not clear how many Americans have been tested for COVID-19, in part because a mix of federal, state and private labs are now carrying out those diagnostics. But reporting by the Atlantic estimates that as of the afternoon of March 9, fewer than 5,000 people in the U.S. had been tested.
  • Compare that to South Korea, which detected its first case around the same time as the U.S. and has reported the capacity to test 10,000 people a day.
  • Without widespread testing, our picture of the outbreak's spread in the U.S. is faulty.

The bottom line: We should be clearing the fog of war around COVID-19 — not contributing to it.

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Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 3 p.m. ET: 18,364,694 — Total deaths: 695,848 — Total recoveries — 10,965,634Map.
  2. U.S.: Total confirmed cases as of 3 p.m. ET: 4,742,277 — Total deaths: 156,133 — Total recoveries: 1,513,446 — Total tests: 57,543,852Map.
  3. States: New York City health commissioner resigns in protest of De Blasio's coronavirus response — New York ER doctor on pandemic advice: "We know what works"
  4. Public health: 59% of Americans support nationwide 2-week stay-at-home order in NPR poll Atrium Health CEO says "virtual hospital" has treated 13,000 COVID patients.
  5. Politics: Republicans push to expand small business loan program Trump tells "Axios on HBO" that pandemic is "under control," despite surges in infections.
  6. Sports: Indy 500 to be held without fansRafael Nadal opts out of U.S. Open.