Bob Behnken and Doug Hurley left the space station on Saturday night, preparing for a Gulf of Mexico splashdown on Sunday.
She and other top health officials in the Trump administration warn states of a deepening spread of the coronavirus, in both rural and urban areas.
Hard-hit Florida faces hurricane season. The virus is picking up speed in the Midwest, and in other states that thought they had already seen the worst of it.
Bob Behnken and Doug Hurley returned to Earth in the first water landing by an American space crew since 1975.
“We need to do a better job next time” of securing the area, the NASA administrator, Jim Bridenstine, said.
Dr. Deborah L. Birx said the U.S. had entered a “new phase” in the fight against the virus, and urged people to consider wearing masks at home. With a focus on the coronavirus, other deadly diseases are making a comeback.
Tuberculosis kills 1.5 million people each year. Lockdowns and supply-chain disruptions threaten progress against the disease as well as H.I.V. and malaria.
A researcher fed beetles to frogs. The encounter did not end as expected.