White House coronavirus task force coordinator Dr. Deborah Birx said on Sunday that the U.S. is in a "new phase" of the pandemic, urging people to follow public health guidance as cases continue to climb in many parts of the United States.

"What we're seeing today is different from March and April," Birx said on CNN's State of the Union."It is extraordinarily widespread — it's into the rural as equal urban areas."

The U.S. has surpassed more than 4.6 million confirmed cases of the coronavirus and 154,000 deaths, according to data from Johns Hopkins University. Cases have skyrocketed in many Southern and Western states in recent months, and members of the White House's coronavirus task force are warning of emerging hot spots in the Midwest.

The latest national ensemble forecast, published by the Centers for Disease Control and Prevention, predicts the U.S. could record as many as 182,000 total deaths by Aug. 22, just three weeks away.

Birx told CNN that projections for a death toll by the year's end depend on how states accelerate and maintain their mitigation efforts, particularly in the South and West.

"Public health is called public health because it has a public component, and we need all of the public to help us get in control of this virus," she said, urging Americans to wear masks in public, practice social distancing and avoid crowded gatherings.

Birx emphasized that unlike the series of outbreaks in metro areas earlier this year, the virus is prevalent in both urban and rural areas. She said people in rural communities are "not immune or protected" from it.

"And that's why we keep saying no matter where you live in America, you need to wear a mask and socially distance, do the personal hygiene pieces," she said. "But more importantly, if you're in multigenerational households and there's an outbreak in your rural area or in your city, you need to really consider wearing a mask at home, assuming that you're positive, if you have individuals in your household with comorbidities."

She deferred to CDC guidance about school reopenings, though she said areas with high caseloads and active community spread should "distance learn at this moment so we can get this epidemic under control."

Birx also defended the federal government's handling of the pandemic, including her own.

House Speaker Nancy Pelosi criticized Birx on ABC's This Week on Sunday, accusing her and the president of spreading disinformation and saying she lacked confidence in Birx.

Birx said she respected Pelosi and her dedication to the American people, and she condemned a July New York Times article that characterized her as delivering misleadingly optimistic reports about the spread of the virus.

"I have never been called Pollyannaish, or nonscientific, or non-data-driven," Birx said. "And I will stake my 40-year career on those fundamental principles of utilizing data to really implement better programs to save more lives."

In response to a question about whether the federal government should "reset" its approach, Birx said she believed it did so about five or six weeks ago, as cases exploded in the South, by shifting to a local framework.

She said they are providing governors with reports and recommendations tailored specifically to local conditions.

Adm. Brett Giroir, a physician who oversees the federal government's testing response, also said on Sunday that public mitigation measures such as wearing masks and avoiding crowds can reduce the spread of the virus, as medical experts learn more about how to treat it.

Giroir told NBC's Meet the Press that while there are some promising medical interventions, hydroxychloroquine — an anti-malaria drug touted repeatedly by President Trump — is not one of them.

After five randomized controlled trials, he said, there is no evidence that hydroxychloroquine is an effective treatment for the coronavirus. In response to a question about whether mixed messaging could lead to misuse of the drug, he said most physicians are not likely to prescribe it.

"I think most physicians and prescribers are evidence based and they're not influenced by whatever's on Twitter or anything else, and the evidence just doesn't show that hydroxychloroquine is effective right now," Giroir said. "I think we need to move on from that and talk about what is effective."

He cited other more promising medical treatments such as remdesivir and steroids, as well as ongoing work with immune plasma and vaccine development.

Wearing masks and avoiding large gatherings and indoor crowds can help reduce the outbreak and avoid the need for a complete shutdown, Giroir said, pointing to states like Arizona that have implemented such policies and are seeing a downward trajectory of cases.

He noted that deaths will continue to increase because mortality lags by several weeks.

According to the CDC, the U.S. recorded 58,947 new cases and 1,132 new deaths on Sunday. New forecasts predict the number of weekly deaths to increase over the next month, with between 5,000 and 11,000 new deaths expected the week ending Aug. 22.

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