Serious outbreaks of the novel coronavirus have now hit several countries outside of China as far apart as Iran, South Korea and Italy. U.S. health officials now say it is likely to start spreading here at the community level, and they are warning that the disruptions to daily life could be “severe.”

“It’s not so much of a question of if this will happen anymore but rather more of a question of exactly when this will happen,” said Nancy Messonnier, director of the U.S. Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases in a news briefing on Tuesday. She urged Americans to begin preparing for such an eventuality, which could include school closures, requests from businesses for staff to work from home and other social-distancing measures.

The CDC has been preparing for the possibility of an influenzalike pandemic for the past few decades. The agency has developed a framework to guide the public health response and is now in the process of adapting it for the novel coronavirus disease (officially called COVID-19). The World Health Organization has not yet declared the COVID-19 situation a pandemic, but health officials say the public should be prepared for one.

Scientific American spoke with Caitlin Rivers, a senior associate at the Johns Hopkins Center for Health Security and an assistant professor in the department of environmental health and engineering at Johns Hopkins University, about what steps communities and individuals can take if the virus starts spreading widely in the U.S.

[An edited transcript of the conversation follows.]

Do you agree with the CDC’s assessment that the virus is likely to spread here in the U.S.?

I do think that we will likely see community spread in the U.S. We've seen, from the experience of China and from other countries that are already experiencing community spread, that it is a difficult virus to contain. And so I think we should proceed with the expectation that we will see something similar to community transmission in the U.S.

When you say “something similar,” do you mean on the scale of what has happened in China?

I don’t think we have a clear idea, right now, of what that will look like. Outside of Hubei, which is the most affected province in China, I think that other provinces in China have had different experiences. So there’s reason to hope and to believe that we will experience a less severe outbreak. But there’s a lot of unknowns right now. And I think the most prudent course of action is to lean into preparedness and to make sure that we’re doing everything we can to mitigate the impact here.

China has taken fairly draconian measures to quarantine people. Do you think something on that level could be imposed in the U.S.? Or would we have to take a different approach?

I don’t want to see those measures implemented in the U.S. The CDC has an extensive community-mitigation plan already created generally, not specific to COVID-19. I understand that they are revising that plan and updating it to make recommendations for how it will fit in with COVID-19. But the CDC plan recommends things such as people voluntarily staying home when they’re not feeling well, staying home even if they are feeling fine if they have the opportunity to—maybe closing schools; maybe limiting businesses. I don’t think we had a clear idea yet of what to expect on that front. But I don’t want to see cordon sanitaires [restriction of people’s movement from a geographical area where a disease is spreading] in the U.S.

What are some steps that schools or businesses can take to decrease the risk of spreading the virus?

A couple of things come to mind. One is for businesses thinking about ways to allow workers to stay home through teleworking or remote work or whatever that looks like. I think that is a good opportunity for people to reduce the number of contacts they have in the community. I think it’s good for communities to think about who is most vulnerable—particularly in the context of this outbreak, it tends to be older people and those with underlying health conditions. So [we could be] making sure that we have good infection prevention and control plans in long-term care facilities and elder centers and other places that have a high concentration of vulnerable older adults. If there are school closures recommended by the CDC, I expect they will be accompanied by guidance of when that would be appropriate, under what circumstances, how long schools would be closed and those kinds of details. So I would expect that communities should get more information from the CDC if that does become a recommendation.

How severe do things need to be before we start implementing measures such as school closures or working from home?

I think the easy measures to take—such as if you have a job [in which it] is convenient to work from home—I think that it would be all right to do them as soon as we start to recognize spread in the U.S., because the costs of them are very low. For interventions that are more disruptive, I think it’s a much tougher balance, because in order to be maximally effective, we want to implement them early in the outbreak. But we also don’t want to needlessly disturb or interrupt people’s everyday lives. And so it is the responsibility of local and state and CDC public health departments to assess that balance and make recommendations.

What are some steps individuals can take?

To avoid spreading a virus, [what you should do is] very similar to what is recommended during flu season, which is to cover your cough, stay home if you’re not feeling well, wash your hands. In addition to that, there’s some good guidance on the Web site [at] that recommends some actions that people can take now in order to prepare their homes if there is community disruption. Some of the recommendations on that are to make sure that families have supplies of their medications and [to] have stores of food and other household supplies just so that if there is a time when it’s not a good idea to go out into a community space, you have enough at home in order to keep yourself comfortable.

What steps are you, personally, taking to protect your family?

I went to the grocery store yesterday, and I bought a couple extra things just to make sure that if it’s not convenient for me to get to the grocery store, I have things on hand. I don’t have any medications that I need to keep on hand, but I would be prioritizing that if I needed them. It’s not the kind of thing that you’re going to regret [doing].

What about masks? I know there’s not a lot of evidence that they can prevent infection, and we also need to reserve them for health care workers.

Masks are not particularly helpful to keep healthy people healthy. They’re really good for making sure that sick people don’t cough or sneeze into the into the air and into their hands, and so on. They’re not recommended for use by healthy people. And it is true that there are concerns about the supply chain for personal protective equipment for health care workers. And so I do think it’s a priority to make sure that health care workers have the supplies they need to stay safe.

What are you most concerned about? Do you see any weak points in our response to the virus?

I think we need to urgently expand our diagnostic-testing-capacity strategy. I think it’s really important that we make diagnostics available to state and local public health departments and hospitals across the country. I think we’re seeing that large testing capacities have been really helpful to other countries that are already experiencing community transmission. And so I think we need to make that a priority.

Right now, testing for COVID-19 in the U.S. is based on a travel history to affected areas or close contact with infected people. Should that be expanded?

I think we need to move toward testing much more broadly. I think we should be testing people with pneumonia who are at hospitals, and people with acute respiratory disease. I think we should also be testing our Influenza-like Illness Surveillance Network [a system of healthcare providers around the country that test a subset of people for flu and similar illnesses], which I understand is a strategy that will be starting soon. But I think we need to really lean into that, because without that widespread testing we can't have a good sense of what, if anything, is already circulating in the community. So the sooner we do that, the better.

What would you tell the public about how to respond to the possibility of an outbreak in the U.S.?

One response I see sometimes that worries me is an inclination to stigmatize—or have an idea that we can keep at bay—a certain group of people or [to] implement a cordon or any sort of discriminatory action. But if we do face tough times, we’re really going to need to get through it together. And so I think it’s really important that communities focus on cohesion and helping one another. And I think that is only going to improve our resilience. So I would encourage people and communities to really focus on sticking together.

How concerned should we be?

I’m concerned, and I think we are in the zone where it’s possible that this will be a severe event. I think there is enough uncertainty that it’s possible that we will face something less than a severe event. But I think, right now, we have an opportunity to prepare ourselves and our communities for something very disruptive. And I think it’s really in our best interest to take advantage of this time.

Read more about the coronavirus outbreak here.