Fox News medical contributor Dr.

Marc Siegel joins Tucker Carlson with insight on 'Tucker Carlson Tonight.'.

A retracted study on hydroxychloroquine and news that the coronavirus may be mutating drew reactions Friday night from Fox News medical contributor Dr.

Marc Siegel.

It's been studied in the lab as an antiviral," Siegel said.

We heard the same thing out of northern Italy," Siegel said.

They want to be able to spread more easily," Siegel said.

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