3 ms·

Almost certainly not. If it had been around for three months, with no control at all, it would be extremely obvious by now.

• jp57 7y ago
  That's fair, I guess, unless there are many unreported mild cases where infections don't result in pneumonia. Also, it's only been two months since christmas, not three, and many schools' winter breaks last into January, so maybe more like 1.75 months for it to spread from the hypothetical vector of returning Chinese students?
  • knzhou 7y ago
    Sure, but just trace the exponential growth curve China started with two months ago, without the flattening out due to quarantine measures. If this were true, we would have more infections than China by now, people would have noticed.
    • pbourke 7y ago
      We will know more when/if widespread serology testing ramps up. As I understand it, this tests for the presence of antibodies for the coronavirus and thus gives a snapshot of recent infections across the population.
    • jp57 7y ago
      In fact the first symptomatic case in Wuhan was identified on Dec 1, and by Jan 16 there were 41 cases of pneumonia identified. That is about the same span of time as between the end of winter break and today. And Wuhan is a dense city of 11 million while I live in a relatively sprawling American city of < 2 million with essentially nonexistent public transit, so transmission could be slower. Alos, I don't know what typical air quality is like in Wuhan in the winter, but given what I've heard about Chinese cities, more severe impact of respiratory symptoms in China seems plausible too. In any case, I agree that there's a fair amount of uncertainty, but a verdict of "certainly not" seems unwarranted.