China was on an exponential curve until they took public health measures at which they went on a different curve. And this is familiar territory. pg is very a

China was on an exponential curve until they took public health measures at which they went on a different curve. And this is familiar territory. pg is very aware that "your current exponential curve is adjustable". So any country whose curve goes the wrong way needs to adjust their actions, and the sooner the better. But once behavior is adjusted, that projection stops being accurate. So his comment is that, based on current infection curves, the level of effort outside of China is way too little for the threat. Turning that around, if dramatic effort causes the disease to have a halving time of 3 weeks, then every day we wait to implement those changes is a week longer that we will have to live under a dramatic regime to limit total casualties.