For all that’s still being discovered about the novel coronavirus, one thing was clear from the beginning: It moves.
In just a few months, it sprinted around the world and left in its wake a trail of death, social paralysis, and economic ruin. Now, as some U.S. states start to lift pandemic-related restrictions on businesses and public spaces, there is a fear that infections will resurge in those places — and that if that happens, the virus won’t stay put.
“That’s like having a peeing section in the swimming pool,” Jeffrey Duchin, a public health official in Seattle and King County, said during a recent panel discussion, citing a phrase someone had mentioned to him. “It doesn’t stay where you started.”
States including Georgia, Texas, and Colorado are tiptoeing into reopening stores and businesses, restarting nonessential medical procedures, and, the hope goes, reviving comatose economies. But as people move around and come into contact with others, the virus has a chance to find new people to infect. If cases build up in one place, it’s more likely that they will spill over — that infected people will get in their cars or board a flight or hop on a bus and potentially ignite new spread at their destinations.
“I do believe we are going to see additional surges of cases from this epidemic, and that will not be contained within a state,” said public health preparedness expert Crystal Watson of the Johns Hopkins Center for Health Security. “So neighboring states and perhaps states across the country and countries across the world are going to have cases imported from those outbreaks.”
The question about ripple effects, now facing governors, is a version of one that will confront universities, employers, sports leagues, and others as they consider how to get back to a semblance of their previous normals. Whatever precautions they might take — staggered shifts, temperature checks, capacity limits — places that bring people together could promote viral spread. And that won’t stop at the office parking lot or the university gate or stadium exit.
“If a company chooses to go back to work, what’s the role of that company if they end up seeding infections to the wider public?” said epidemiologist Michael Mina of Harvard’s T.H. Chan School of Public Health.
Universities might think it’s worth the risk to bring back students, because younger people overall have milder infections and are less likely to die than older people (though some do get severe cases of Covid-19, the disease caused by the virus). If that happened, Mina said, “and young people start transmitting among themselves but largely asymptomatically or with mild symptoms, if you don’t look deep enough at the question, you might say, ‘Great, we’re building up herd immunity.’ But then those young people will inevitably start seeding outbreaks to the wider community, and anyone else can be at risk.”
No one knows how quickly and how expansively the spread of the virus will pick up as states roll back restrictions, and governors are generally outlining gradual changes. In Georgia, gyms, salons, and restaurants are operating with limits. In Colorado, retail stores can have curbside pickup and elective surgeries are back on. And starting tomorrow, malls, theaters, and restaurants in Texas can open with 25% occupancy. These and other states have plans for further easing of distancing policies as long as case counts don’t spike.
The problem, experts say, is that diagnostic testing remains so limited that a second surge of cases could silently build. The Trump administration’s goal of conducting 2 million tests a week is below what most experts say is needed to adequately track the virus, and that plan won’t be in place until at least the end of May.
Even if people do get tested, sometimes the results aren’t returned for days. People can spread the virus before they start showing symptoms, and some people don’t show signs of the disease at all. Governors are gauging their epidemics by the strain on health care systems, but by the time a spike in an outbreak sends enough people to the hospital to make itself obvious, it might have grown beyond control.
“We really don’t know enough about the virus to know if we start opening up hair salons and restaurants and all the things that we’re normally used to in our society, what will happen when people start mingling again?” Mina said. “There’s a lot of fear that if that happens without the appropriate surveillance efforts in place, that we could find ourselves in a situation again like we just found ourselves in two months ago.”
The different approaches states are taking could lead to further divisions among them. As infections increased initially, some governors asked people coming into their states to quarantine themselves for 14 days so they didn’t ignite new spread of the virus. There have not been any domestic U.S. travel restrictions, though at one point, the Centers for Disease Control and Prevention asked most people in New York, New Jersey, and Connecticut to avoid heading elsewhere.
For states that are keeping lockdowns in place, the best protection against the threat of imported cases is one they’ve already deployed. Because so many people are staying at home, if a person carrying the virus flew from Atlanta to Boston or Cleveland or Seattle, they wouldn’t come into contact with many people, reducing the chances that a new cluster of cases could form.
Beyond that, experts’ recommendations to detect imported cases are the same steps they say are needed to control the local spread of the disease. Test widely to identify cases, isolate people who are sick, and track down and quarantine people they’ve encountered to see if they contracted the virus.
“What neighboring states can do is really to build this capacity to find every case and trace their contacts, because that will suppress any other surges, but it will also find those cases that are imported from other outbreaks,” Watson said.
As businesses reopen, what will also influence whether the virus takes off is how individuals respond. Just because they can go to stores or movie theaters or restaurants doesn’t mean that they will. Many people feel it’s still not safe enough to gather in groups. Steps like hand washing and isolating oneself when sick have major impacts.
“It’s possible that even if some of these mandates are released that people will still take some time to go back to normal,” said disease ecologist Ana Bento of Indiana University, whose research has shown that people started sticking at home as awareness about the virus grew, even before the shelter-in-place policies. “Yes, we will definitely see an increase in transmission, but hopefully what we’ll see, like what we saw at the beginning of the epidemic, is people changing their behavior.”
Bento also warned that in addition to a secondary surge of cases spilling into other states, it could also accelerate the spread of the virus into rural places that so far have remained protected.
“No population is closed,” she said.