In an interview with CBS's "Face the Nation on Sunday," Gottlieb said that in the absence of requirements for the "universal masking" of people in affected states the spread of the virus was likely to continue growing.
Requiring people to wear masks is "the simplest intervention that we could take" to stop the spread of the virus, Gottlieb said. Polls, including the CBS survey, show the issue of wearing masks has become highly politicized in the U.S.
While the virus has ebbed in the Northeast, states like Florida, Texas and Arizona have seen virus cases spike in recent days. Other measures, including hospitalizations and deaths, haven't risen as much.
On Sunday, Florida officials said the state's coronavirus cases rose 6.4% from a day earlier. Cumulative hospitalizations of Florida residents rose 0.8%.
The current record rates of newly reported cases at 40,000 or more in recent days likely reflected a far bigger outbreak, Gottlieb said.
By the CDC's own reckoning, the real number of infections was 5 to 10 times that being reported, Gottlieb said, and that meant the real rate of new infections was likely to be a "quarter-million" each day.
Frieden said that while there were potentially encouraging signs in the growing share of younger people -- who are less likely to suffer severe complications -- among new reported cases, that shouldn't be a reason to grow complacent.
"What starts in the young doesn't stay in the young," he said, as younger people, often asymptomatic, can spread the coronavirus to more-vulnerable individuals including family members and co-workers.
It was false to dismiss the recent surge in daily cases as a function of a ramping up in testing, Frieden said. A lower death rate was also potentially misleading, he said, with reported deaths likely to lag a surge in cases by about a month.
(Frieden is currently chief executive of Resolve to Save Lives, which is funded by Bloomberg Philanthropies, whose founder, Michael Bloomberg, is also founder and majority owner of Bloomberg LP.)
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