Mitigation requires heavy social distancing. People need to stop hanging out to drop the transmission rate (R), from the R=~2–3 that the virus follows without measures, to below 1, so that it eventually dies out.
These measures require closing companies, shops, mass transit, schools, enforcing lockdowns… The worse your situation, the worse the social distancing. The earlier you impose heavy measures, the less time you need to keep them, the easier it is to identify brewing cases, and the fewer people get infected.
This is what Wuhan had to do. This is what Italy was forced to accept. Because when the virus is rampant, the only measure is to all the infected areas to stop spreading it at once.
With thousands of official cases — and tens of thousands of true ones — this is what countries like Iran, France, Spain, Germany, Switzerland or the US need to do.
But they’re not doing it.
Some business are working from home, which is fantastic.
Some mass events are being stopped.
Some affected areas are in quarantining themselves.
All these measures will slow down the virus.
But it’s not enough to get this transmission rate, this R, from 2.5 to 2.2 or even 2. We need to get it to below 1 for a sustained period of time to kill it. And if we can’t do that, we need to get it as close to 1 for as long as possible, to flatten the curve.