When China started the lockdown of Wuhan on Jan 23, they may only have had 830 confirmed cases - but the number of confirmed cases was basically limited by the

When China started the lockdown of Wuhan on Jan 23, they may only have had 830 confirmed cases - but the number of confirmed cases was basically limited by the rate at which they could test people turning up at hospitals with severe symptoms and continued to be so for quite a while, from what I can tell. There's a more interesting figure buried in the WHO's final report from their joint mission to China: at some point, someone went and retested old samples taken from people in Wuhan with flu-like symptoms, 20 per week. They found no positives before January, 1 in the first week of January, and 3 in the second week. Those are not pretty numbers.