SAN FRANCISCO – Six Bay Area counties in California are under quarantine for three weeks. The Centers for Disease Control and Prevention has urged no group gatherings for two months. President Donald Trump said relief may come by August. And leaked British documents projected a coronavirus outbreak could rage until spring 2021.

As parts of the U.S. head into a coronavirus lockdown, it's unclear how long these severe restrictions will last. Only one thing is certain: The nation's COVID-19 crisis will be as bad as we let it get.

Scientists, government officials, historians and cultural observers say the size and duration of the outbreak will depend on our collective actions over the next few weeks and months. The promising news, they say, is that we have the power to not just resist, but also to come together as a country in a way reminiscent of World War II.

“Back then, the government and the public joined to mobilize for the war effort, producing armaments and food, and that same effort is needed here,” says Timothy Massad, senior fellow at Harvard University’s Kennedy School of Government and chairman of the Commodity Futures Trading Commission under President Barack Obama.

“The government should mobilize the private sector to get more virus testing kits, more hospital beds, more ventilators," he says. "We need to treat this like a fight that everyone from the top down needs to rally for to end this sooner rather than later.”

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As alienating as the effects of a coronavirus quarantine can be, isolation – in form of the growing number of city- and county-mandated orders to shelter in place with the exception of trips out to buy necessities – is crucial to bringing this outbreak to an end. There are no vaccines or treatments yet, so staying clear of one another is key to flattening the pandemic's contagion curve.

"This all hinges on how people behave," says Natalie Dean, a biostatistician at the University of Florida-Gainesville specializing in the statistical analysis of infectious diseases such as Ebola and HIV. "Things will get more severe before they get better. It's going to be a shock to the system for some people."

But everyone staying home for weeks or months comes with its own range of issues that could include unemployment, new child care costs and, foremost, the stressful byproducts of isolation.

"Hugging, seeing people's faces, they're an important part of how we connect and feel safe," says Elissa Epel, professor in the department of psychiatry at the University of California-San Francisco. "We are going to make an extra effort to stay connected in the ways that we still can to get through this."

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COVID-19: Will the US follow Italy or South Korea?

A hint at how long this all might last comes from China. In Wuhan, the epicenter of the outbreak about 2½ months ago, life is slowly returning to normal as reports of new COVID-19 cases ebb. That could signal an abatement there by late May.

But Italy offers a more harrowing and urgent marker. Experts say that much like the U.S. government’s lagged response to the virus when it first appeared, Italian officials initially responded with less urgency than Asian nations such as South Korea and Singapore.

Italy has since been hit hardest in Europe by COVID-19, with 31,000 cases and more than 2,500 deaths in a country of 60 million. A YouTube video gone viral features Italians giving themselves “from 10 days ago” advice. Virtually all the messages are identical: Shame on me for initially not taking this seriously enough.

So far globally, there have been about 200,000 cases with nearly 8,000 deaths. The U.S. has seen 6,500 cases and more than 100 deaths. A recent British report suggested that without action from the U.S. government or its public to halt the spread of COVID-19, more than 2.2 million Americans could die from the virus.

“People here probably still don’t yet understand the severity of things,” says researcher Dean, noting that some Florida beaches were packed this week with spring break revelers. “The measures some cities are taking in terms of quarantine may sound extreme when you look outside and everything seems normal. But they’re appropriate.”

If perhaps a bit too late. Lawrence Wright, a staff writer at The New Yorker, spent years talking to experts on pandemics and viruses for his eerily prescient forthcoming novel, “The End of October,” in which a deadly flu ravages a surprised world.

While Wright doesn't believe COVID-19 will prove to be the worst-case scenario conjured in his book, he is nevertheless shocked at the how the U.S. was caught on the back foot for this pandemic.

"I did all the research into what this could look like, but watching it unfold in real life highlighted how little preparation we had for this," he says. “This pandemic may well still be a devastating event for us. It’s wounding. It takes a bite out of life to be separated from people we love.”

Wright, who lives in Austin, says he has had a regular Monday breakfast meeting with friends for the past 30 years. This past Monday, the meal turned into a walk. "Even that made me feel nervous," he says. "You don't know where a contagion may arise."

That sort of caution contrasts with pockets of the U.S. where bars and restaurants remain open despite health official warnings to avoid groups sizes as small as 10.

A cavalier attitude toward the virus – which in turn could get in the way of slowing its spread, especially since asymptomatic carriers can pass it along – could be partly the result of Hollywood's love of dramas starring bacteria and zombies, says Canadian writer and director Jeff Barnaby.

“We have spent so much time dramatizing events like this that we then are underwhelmed by the actual thing,” he says, referencing movies such as 2011’s “Contagion” and the hit TV drama “The Walking Dead.”

Barnaby's new movie adds to that oeuvre. "Blood Quantum," whose release was delayed by the virus, finds the Mi’gmaq Native American director spinning an allegorical story about indigenous peoples being attacked by white zombies.

“When your brain is conditioned like that, it makes for a climate where everyone’s casual about the real thing,” says Barnaby, who planned to hole up in his Quebec apartment after hearing that his movie’s publicity tour was canceled. “That causal approach then is what brings on the exponential growth threat. So who knows when this thing ends.”

Coronavirus can bring our best selves

Given our state of uncertainty, some say it’s better to focus not on when this global nightmare will be over but rather on how we can be our best selves during these unsettling times.

“We shouldn’t call this the new normal, because nothing about this is normal,” says Pepper Schwartz, sociology professor at the University of Washington. “We don’t know what we’re dealing with today, and we don’t know what will come tomorrow. So we have to adapt.”

Schwartz says it’s important to take stock of the good things in your life to put these times in perspective.

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Consider the conditions for the homeless and the working poor who may lose their jobs, she says. Or working parents suddenly facing child care challenges to keep their employment. And have compassion for those both famous and unknown who have tested positive for COVID-19.

Feeling grateful will help mitigate the inevitable stress that comes with being in close quarters with spouses and family, and perhaps steer couples away from divorce and families from arguments, says Schwartz, who lectures globally on issues facing couples.

“I tell people, this is a time to be ambitious,” she says. “Ask more of yourself in terms of patience, generosity and compassion. Be empathetic, because in times like these tempers and anxiety flare.”

Orlaith Murphy and her Bay Area family now start each morning with three minutes of meditation. “It’s important more than ever to be thoughtful about what you can and cannot control,” says Murphy, who works for a large San Francisco-based retailer.

She and her husband Justin, a cybersecurity expert, are hunkered down working from home alongside their 9-year-old twins in the small Bay Area suburb of Mill Valley, whose picturesque downtown looks increasingly like an abandoned movie set.

“We have to band together and see what’s needed for the greater good of the community,” she says. “We are all in this together.”

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If there is indeed one certainty, historians, scientists and artists say, it is this: When this staggering global outbreak finally ends – and it will end – there will be reckoning of sorts, one that will judge how we responded as a nation, as communities, as friends.

Epidemics, wars, terrorist events and natural disasters have preceded COVID-19, and in each of those instances human beings were presented with an opportunity to define their very humanity, says author and Rice University history professor Douglas Brinkley.

“In American history, this outbreak stands with maybe Pearl Harbor and 9/11 as a massive shock to the national system,” says Brinkley, who is at work on a book about how the environmental movement of the 1960s brought about global change. “This, too, can have a huge galvanizing effect in making a new America.”

Much the way past social crises gave rise to the Food and Drug Administration, child labor laws and a clean-up of the meat packing industry, Brinkley says our shared COVID-19 trauma could renew calls for public health, create SWAT teams for future pandemics, and find more college students going into the medical field.

“There are moments that transcend politics and become bipartisan movements, like the push to go to the moon,” Brinkley says.

Rob Citino, executive director of the Institute for the Study of War and Democracy at the National World War II Museum in New Orleans, notes the things the U.S. accomplished under the crucible of war "changed us as a nation for the better.”

Citino says that some 80 years ago, when confronted with the challenge of vanquishing Nazi Germany, Americans did what they had to – rationing gas, food and clothing, working overtime in factories and sending loved ones into battle.

“I see that as another parallel to today’s crisis,” Citino says. “We don’t have a timeline, but we’re in this for the duration as a nation and it’s going to last until it’s over. And then we’ll be back, perhaps with a new perspective on ourselves.”

Follow USA TODAY national correspondent Marco della Cava: @marcodellacava