What does a shelter-in-place order really mean?

As the coronavirus pandemic continues to impact the United States and countries around the world, families are finding daily life increasingly restricted. However, some areas might see even stricter rules come into place as shelter-in-place orders are enacted.

The orders have already been enacted in San Francisco and the surrounding Bay Area. Yesterday, New York City mayor Bill de Blasio told TODAY's Savannah Guthrie that a shelter-in-place order had to be "considered seriously."

TODAY spoke to Johns Hopkins Center for Health Security senior scholar Crystal Watson, who works on public health preparedness, about what a shelter-in-place order might actually look like.

"Shelter-in-place (order) is not something that's used very often," Watson said. "It's typically more applied to disasters — like after a hurricane, for example, you might be ordered to shelter in place. In this case it just means staying at home, not going out unless you absolutely need to, and the terms of that will be defined by the authorities that are implementing the order."

Watson cautioned that a shelter-in-place order would be even more restrictive than current social distancing guidance.

"The current guidance is less restrictive because it allows for personal judgement about whether and when to go out in public," she said.

The specifics of a shelter-in-place order could vary based on the city and the officials making the order.

In the Bay Area, millions of people have been prohibited from leaving their homes "except for essential needs" since Monday night. Pharmacies, grocery stores, banks, gas stations and essential government services are among the only things remaining open. Also excluded from the order are drivers for ride-sharing companies and other delivery services. Those who do not comply with the order will be charged with a misdemeanor.

"The virus is here in San Francisco," said San Francisco's Public Health Department director Dr. Grant Colfax in a news conference. "We must practice social distancing to slow it down ... Every hour counts."

Specifics have not been released on what sort of restrictions New Yorkers could face if they are ordered to shelter in place.

While the restrictions could seem extreme, Watson said that it could be important to help slow the spread of the coronavirus.

"The purpose of shelter-in-place orders would be to further restrict movement and contact so that there are even fewer opportunities for people to become infected and pass the virus to others," she said.