President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE concluded his address to the nation at 9:12 p.m. on Wednesday, seeking to reassure a nervous public that the government was doing everything it could to stave off the worst effects of the coronavirus. Two days later, he declared a national emergency.

The past week was marked by a whirlwind of cancellations, restrictions on travel and public gatherings, and increasingly grim warnings from public health officials.

Five minutes after Trump’s Wednesday speech, news broke that actor Tom Hanks had the virus, the most high-profile American to contract it to date. Twenty minutes after that, the NBA announced its season had been suspended after first one and then multiple players tested positive.

ADVERTISEMENT

By midday Thursday, nearly every major sports league had paused its season because of the virus, Disneyland announced it would close down, multiple movie releases and concert tours had been delayed or canceled, and state and local officials nationwide stepped in to close schools and ban large events.

The week marked a turning point in the U.S. response to the coronavirus in terms of both how public health officials are talking about it and how Americans are responding. With hundreds of new cases being reported every day, state and local governments began taking serious steps to slow the spread of the virus, disrupting daily life for millions of people.

Dr. Anthony Fauci Anthony FauciOvernight Health Care: CDC reverses controversial testing guidance | Billions more could be needed for vaccine distribution | Study examines danger of in-flight COVID-19 transmission Trump claims enough COVID-19 vaccines will be ready for every American by April Gates says travel ban made COVID-19 worse in US MORE, one of the top scientists leading the coronavirus response, warned Friday that those disruptions could last up eight weeks or more.

“It's going to be at least a matter of several weeks,” Fauci said Friday on “Good Morning America.”

“It’s unpredictable, but if you look at historically, how these things work, it'll likely be anywhere from a few weeks up to eight weeks or more.”

A confluence of events over the last seven days led to a shift in how the U.S. is addressing the virus.

ADVERTISEMENT

The number of confirmed cases began rising rapidly each day as more testing was done. Growing numbers of community-spread cases in New York, Washington state and California led officials there to ban large gatherings, close schools and take other measures to slow infections, setting the stage for other cities and states to do the same.

Officials in Washington and Ohio warned that there could be thousands of people walking around with the coronavirus who don’t even know it because testing still hasn’t scaled up enough to be on par with other countries, six weeks after the first case was detected on American soil. As a result, officials are preparing for the worst.

“Tons and tons of testing is necessary,” said Adriane Casalotti, chief of government and public affairs at the National Association of County and City Health Officials.

“And so that is another huge focus in areas where there aren't any confirmed cases. Is it that they don't have coronavirus in their community, or they just don't know it yet because of the testing delays?”

Meanwhile, the government in Italy, which is viewed by some as a peer nation, put much of the country on lockdown to try to halt its own crisis. Fears grew that if the virus wasn’t slowed in the U.S., American hospitals could exceed their capacity to treat patients, as is the case in Italy.

Trump has spent weeks minimizing the threat of the virus to the mainland U.S. He has repeatedly insisted his administration has COVID-19 under control and favorably compared the number of deaths thus far domestically to the common flu or to other countries dealing with more serious outbreaks.

But the tone among public health officials shifted this week, growing far more urgent.

Fauci repeatedly laid out in stark terms that the virus will continue to spread and that “things will get worse than they are right now.”

Surgeon General Jerome Adams Jerome AdamsTop health officials pledge to keep politics out of COVID-19 vaccine process The Hill's 12:30 Report — Presented by Facebook — Trump, Biden duel in final stretch | Vaccine trial on pause after recipient's 'potentially unexplained illness' | Biden visits Michigan | Trump campaign has 18 events in 11 states planned in the next week Watch live: Senate hearing on vaccines MORE warned Tuesday that “we have not hit the peak of this epidemic quite yet.”

Even Trump sounded like he appreciated the severity of the situation this week. He restricted travel from Europe on Wednesday, and by Friday, he had declared a national emergency to mobilize additional resources to fight the spread of the virus.

Americans appeared to heed the warnings. Many grocery store shelves were bare as shoppers stockpiled food, toilet paper and other goods for potentially lengthy periods of self-isolation. Popular tourist sites were shuttered, and multiple movie releases and concert tours have been delayed or canceled.

“We’re currently in a worrisome situation because this is a disease for which people do not have natural immunity from past exposure, and there’s currently no vaccine and no treatment,” said Vicki Bier, a professor at the University of Wisconsin-Madison who specializes in risk analysis for homeland security.

ADVERTISEMENT

“I don’t want to say this is the new normal,” she added. “Hopefully we’ll be back to something more similar to the old normal, but I think it’s useful to be thinking these kinds of measures may be needed for significant periods of time.”

Actions in the coming days and weeks will be key for slowing the spread of the virus and reducing the peak of the outbreak, experts say.

“We're at a critical point now — more in some regions of the country than in others — but in general, the kinds of things that are going on will hopefully make that blunting of that peak so that we could save a lot of lives,” Fauci said.

As more testing is conducted and more cases are confirmed, it is expected that more schools will close, more events will be canceled and more people will begin working from home.

Trump on Friday vowed to overhaul the coronavirus testing approach in the U.S., with “drive-thru” options available in some locations. It’s not clear when the new program will be fully ramped up, but Trump said half a million additional tests will be made available next week.

A scaled-up approach to testing should give a better idea of how widespread the outbreak is in the U.S.

Some forecasts put the eventual number of infections caused by the outbreak in the millions.

"This is something that doesn’t have a clear end in sight," Casalotti said. "So it's important to balance the messages of 'yes, we need to take action now.' But really, this is a change in how we are going to be living our lives for the foreseeable future."