You're right, rino, he never tweeted that.
He probably would have though, if he hadn't been balls deep in trying to have Trump impeached at that time, due to his towering case of TDS.
Trump declared a public health emergency on 1/31/20, including a ban on travel from China, and was, as anyone who knows the Pavlovian response from snowflakes could predict, roundly criticized for xenophobia, racism, etc., by the media.
As even CNBC, no Trump fans by any stretch, pointed out in an op/ed piece on 2/26/20, it would have been nice if Schumer had defended Trump's move, at the time. But as I already mentioned, Schumer was a little too busy trying to get rid of the Tangerine Tornado to pretend to worry, or even care about the well being of the American public.