You are right, they were infected a few days before (I think 6.6 on average). But still, the growth was 10x in ten days as you can see on the graphs. It's just

You are right, they were infected a few days before (I think 6.6 on average). But still, the growth was 10x in ten days as you can see on the graphs. It's just that the measurements are always a few days behind the real numbers. In other words, there is a delay in the system, but it does not change the shape of the graph, it simply shifts it right (towards the future) on the time axis.