Fox News medical correspondent Dr. Marc Siegel said on Tuesday that there is “viral spread” ongoing because there is no vaccine yet for the coronavirus.

“We have public health measures, distancing, with all the things you just heard the president suggesting today and they are suggestions, but they need to be followed to decrease and stamp down on viral spread,” Siegel told “Fox & Friends.”

Siegel also said that since the “denominator” of those infected is “unknown,” matters should be taken more seriously.

“We need to test millions to know where we are with this virus,” Siegel said.

SANDERS HINTS TUESDAY’S PRIMARIES SHOULD BE POSTPONED OVER CORONAVIRUS

Trump announced on Monday a set of guidelines that he said Americans should follow to prevent the further spread of the coronavirus — despite admitting that the pandemic could stretch into July or August.

Speaking during a briefing of the coronavirus task force, Trump outlined a plan to slow the spread of COVID-19 in 15 days.

“With several weeks of focused action, we can turn the corner and turn it quickly,” Trump said. “Our government is prepared to do whatever it takes.”

Officials recommended that large swaths of the population isolate themselves and everyone avoid social gatherings or groups of more than 10 people.

They also said Americans should work from home if possible; avoid eating or drinking in bars and restaurants; and “avoid discretionary travel, shopping trips and social visits.”

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Siegel advised pregnant women to seclude themselves from work environments, though it is not medically confirmed yet whether the coronavirus transfers from mother to a newborn.

“Stay away from work environments,” Siegel said.

“Pregnancy is a form of slightly being immunocompromised -- your immune system is tied up, protecting you, protecting your unborn child -- I don’t think you should put yourself at risk.”