In many ways, the COVID-19 pandemic has proven to be a moving target. Faced with stopping a pandemic scientists have yet to fully understand, researchers simply can’t guarantee what lies ahead—or when life will return to a version of normalcy.

But as businesses continue to shutter and people retreat into their homes, one thing has become clear: To stem the spread of disease, Joe Pinsker reports for the Atlantic, strict measures that keep people physically separated could be in place for several months—perhaps even more than a year.

These social disruptions are severe, alarming and difficult to fully comprehend. They also come at an immense psychological cost. Already, mere weeks of closures and separations have taken an immense toll on the world’s wellbeing, sparking major financial losses, widening socioeconomic inequalities and exacerbating the health burden on vulnerable groups.

Experts warn that this is the price that must be paid to stop the pandemic. Not because the costs we’re paying now are negligible, but because what stands to be lost is so immense. The United States now has the most confirmed infections of any nation in the world, surpassing 100,000 cases and 1,500 deaths in total on the evening of Friday, March 27—and it's not yet known when the country will reach peak for new cases. So what happens next?

Immunity is key

When enough of the global population becomes immune, SARS-CoV-2 will lose its infectious toehold, failing to find enough new, susceptible individuals to infect before leaving its current hosts. Researchers estimate that about 2.5 to 5 billion people—roughly a third to two-thirds of the global population—will need to be immune to hit this critical threshold, Jonathan Lambert reports for Science News.

Two possible paths to immunity exist, neither of which is guaranteed. In one, individuals who recover from COVID-19 produce the immune molecules required to fight off the virus, should it try to infect them again. In the other, people become immune by getting vaccinated, teaching their bodies to recognize and destroy the invader without getting sick.

Both resolutions hinge on whether an exposure to SARS-CoV-2, or at least, pieces of it, can protect a person from future infection, which has yet to be shown definitively in the long term.

Flattening the curve

Though many COVID-19 vaccines are now in development, this process takes many months—often years. In the meantime, officials worldwide are scrambling to reduce the rate at which new infections arise to avoid overwhelming an already strained healthcare system.

That’s the idea behind “flattening the curve” of the pandemic’s trajectory: If the virus has fewer opportunities to hop from person to person, communities won’t see a big, rapid spike in new cases; instead, new cases would be spread out over a longer stretch of time, reducing the average number of people sickened with COVID-19 on a given date. Drawing out the pandemic’s timeline also allows researchers to develop much-needed treatments and tests.

The first step to achieving this slowdown is social distancing: drastically reducing contact with individuals, in this case by keeping at least six feet away from others—a distance that largely avoids the infectious droplets sprayed out of the airway of those infected with SARS-CoV-2. (Some psychologists have advocated for the use of the less isolating term “physical distancing” to encourage people to remain socially connected while physically apart.)

Given the infection’s weeks-long trajectory and the virus’ extreme ease of spreading, distancing is not something that will work instantaneously. The tactic effectively starves the pandemic of hosts—something that takes time, and could quickly be thrown off should some subsets of the population waver in their commitment.

If, for instance, distancing measures were relaxed too soon, SARS-CoV-2 could roar back in a still-susceptible population, extending the pandemic’s timeline even farther.

“If we all just went right back to how things were before, transmission would start again with the same intensity,” Johns Hopkins Center for Health Security epidemiologist Caitlin Rivers tells Brian Resnick at Vox.

According to Science News, a minimum of one to three months of strict distancing will likely be required in the United States—and that’s just the beginning. Our battle with COVID-19 will likely extend far beyond that, especially if SARS-CoV-2 waxes and wanes with the seasons, or our immunity to the virus doesn’t hold up for more than a few months or years.

Until a vaccine becomes available, the world may be in limbo with distance policies tightening and relaxing when COVID-19 flares up or subsides, according to Gideon Lichfield at MIT Technology Review.

“We need to be prepared to do multiple periods of social distancing,” Stephen Kissler, an infectious disease researcher at Harvard’s School of Public Health, tells Ed Yong at the Atlantic.

The importance of testing

As Yong reports for the Atlantic, another crucial component is an expedient ramp-up in diagnostic testing for SARS-CoV-2 infections. Without knowing the world’s actual burden of disease—the number of people infected, including those with mild or no symptoms—researchers can’t get a good handle on how the pandemic is evolving, or what populations are most at risk.

Other countries, like South Korea, deployed testing early, allowing them to identify and isolate infected individuals, then monitor their close contacts for signs of disease—a comprehensive strategy that largely curbed COVID-19’s spread, Rivers tells Science News. The United States is beyond the point at which it can mimic this trajectory.

But effective, accurate diagnostics remain crucial to preventing infections at the local scale, and can still slow SARS-CoV-2’s ongoing spread. By mapping out disease hotspots and pinpointing places where infections are more scarce, widespread testing could alleviate some of the most stringent social distancing measures, Sharon Begley reports for STAT.

More tests could also identify individuals who may have recovered from COVID-19, and—if they’re immune—those people could return to work, or help care for vulnerable populations. Critically, making and perfecting these tools now will equip us for any future outbreaks.

An end in sight?

After weeks of strict distancing, some parts of the world—including China’s Hubei province, where SARS-CoV-2 was discovered—are now initiating their “exiting strategies,” according to STAT. Here, the pace of the pandemic has dramatically slowed, following a complete lockdown that kept residents from traveling between cities or even strolling down the street.

With the exception of those in Wuhan, the city where the virus was first detected last year, Hubei residents can now leave the province, provided their health status is clear. Should the case count stay low, more restrictions are expected to be lifted in the coming weeks—though officials are readying themselves to reimpose measures if necessary.

The optimism in Hubei, however, is not universal. In the United States, COVID-19 cases are still skyrocketing by the day, and experts can’t yet forecast when this country’s outbreak will start to fizzle out. For now, many are highlighting success in other countries, and the glimmers of hope emerging in places like Washington state, where new infections are still occurring, but not as rapidly as before, thanks to widespread abidance to distancing.

The road to ending this pandemic is an obviously difficult one that relies, in large part, on the collective resilience of hundreds of millions. Strict distancing will not—and cannot—be sustained forever, and recovering from these measures will require careful attention to both physical and mental health.

But letting up too soon would only worsen the consequences, Lilian Alessa, director for the Center for Resilient Communities at the University of Idaho, tells Nicoletta Lanese at Live Science.

“We literally have to have absolute compliance,” Alessa says. “Without that, this is our new normal.”