The Centers for Disease Control and Prevention (CDC) is preparing for the possibility that the new coronavirus will spread through the United States — and it’s using its guidelines for pandemic influenza as a starting point. The new coronavirus isn’t influenza, so the recommendations probably won’t match what may happen during a coronavirus outbreak. But they’re a useful starting place for US public health agencies.

“Because we have done a lot of planning around pandemic influenza, we have a good head start. But we need to look at the plans and see how the current situation might alter them,” said Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases at the CDC, during a press call at the beginning of February.

Exactly right. Would add that much of our pandemic planning is (rightly) predicated on influenza. That work still has value, but the underlying assumptions should be carefully evaluated to see what should be kept, modified, discarded. https://t.co/Z9ONqTkZky — Matt Watson (@BioAndBaseball) February 24, 2020

There are still only a few dozen people with the confirmed disease caused by the new coronavirus in the US, and the overwhelming majority of cases are people who had recently been in Wuhan, the outbreak’s epicenter, or who were on the cruise ship the Diamond Princess. But there are over 80,000 people sick with the virus around the world, and new hotspots in South Korea, Italy, and Iran are making experts concerned that containing it may no longer be possible.

“Ultimately, we expect we will see community spread in this country,” Messonnier said in a press conference on Tuesday.

The CDC’s pandemic influenza guidelines were updated in 2017 and now include lessons learned from the response to H1N1, or swine flu, in 2009. They outline the actions, outside of drugs and pharmaceuticals, that communities can take to reduce the spread and impact of a global outbreak of a new flu. Those fall into three categories: personal, community, and environmental.

Personal interventions start with common-sense steps taken for any illness: the guidelines say people should wash their hands, cough into their arm, and stay home if they’re sick. During an active, severe outbreak, that intensifies: in those cases, people who live in the same house as a sick person, who are at a higher risk of contracting the illness, should also stay home from work or school to avoid spreading it to others.

Public or community health actions recommended by the CDC are more extreme. The agency might encourage certain areas to close down schools and rely on tele-learning during severe epidemics. That might be done as a precautionary measure before a large portion of a student body gets sick or after administrators start to see illness in students and teachers.

During the H1N1 outbreak in the United States, some schools in areas hit hard by the virus shut down. Nearly all parents supported those decisions and thought they helped reduce the spread of the flu. In Canada, school closures cut the amount of H1N1 circulation by half.

If schools remain open during a severe outbreak, they should keep students apart from each other, including by rearranging desks to space them at least three feet apart. Illnesses like the flu spread when people come into close contact with each other, so keeping them apart can help prevent disease from passing from person to person. Other social distancing measures might include anything from holding teleconferences instead of in-person meetings to canceling concerts or sporting events. Those sorts of actions helped blunt the spread of H1N1 in Mexico during that outbreak.

Those actions can be disruptive, though. People might be reluctant or unable to take time off work if it means lost income, and parents might struggle to find child care if schools close.

Finally, CDC guidelines for environmental precautions say that surfaces should be cleaned regularly in homes, schools, offices, and other public spaces.

These guidelines are just recommendations, and every state and local health department makes decisions on what actions to take (and when to take them) on their own, based on the impact an outbreak is having on each community. Health departments will weigh the relative harm that could come from a disruptive measure, like school closures, against how well it could reduce the spread of an illness. Local health agencies also have to rely on the trust and cooperation of the community. People have to follow the actions those agencies call for in order for them to have an effect.

The CDC is still trying to catch each and every case of the new coronavirus that enters the US, but the agency is also preparing to shift its focus toward limiting the impact of any spread of the virus through the country. “This situation may seem overwhelming, and disruption to every day live may be severe,” Messonnier said. “These are things that people need to start thinking about now.”