The Centers for Disease Control and Prevention has said it is not a question of if but when the coronavirus outbreak spreads in the United States. CDC officials urged Americans to "prepare in the expectation that this could be bad."

But what exactly should you do to prepare? Preparing for the spread of a virus is similar to how you would prepare for a major weather event, said CBS News medical contributor Dr. David Agus.

"We should plan as if a big storm was coming," Agus said.

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For example, he recommends people gather supplies that would allow them to live indoors for several days if necessary — such as non-perishable food, extra water, a two-week supply of all medications, and activities to keep children occupied.

When cases of the coronavirus illness, now known as COVID-19, started proliferating in central China in early January, the government issued mandatory quarantines in major cities in an effort to contain it. Such widespread quarantines would be extremely difficult to implement in the United States.

There are currently only a handful of cases in the U.S., and those patients are being treated in medical isolation. But according to Agus, if more cases erupt, communities could be given little warning before a quarantine is enforced, so staying informed about conditions in your city is important.

"When the quarantine happens, the quarantine happens," he said.

The CDC has urged people to make plans ahead of time for child care and ways to work from home, just in case schools and businesses need to close.

"I had a conversation with my family over breakfast this morning and I told my children that while I didn't think that they were at risk right now, we as a family need to be preparing for significant disruption of our lives," Dr. Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Diseases, said Tuesday.

She recommended that parents ask their children's schools about plans for dismissals, closures, and "teleschool."

"You should think about what you would do for child care if schools or day cares close. If teleworking is an option for you," she said. "All of these questions can help you be better prepared for what might happen."

Agus applauded officials in San Francisco for declaring a state of emergency on Tuesday despite there being no cases of coronavirus in the city. The declaration — which closely followed the CDC's announcement urging Americans to prepare — allows the city to secure funding, mobilize additional resources and expedite the process of emergency planning, CBS San Francisco reports.

"The global picture is changing rapidly, and we need to step-up preparedness," San Francisco Mayor London Breed said in a statement.

The immediate risk of the coronavirus to the American public is "believed to be low at this time," according to the CDC's website.

Still, health officials recommend people take basic hygienic measures to protect themselves against infection — avoiding close contact with people who are sick, washing your hands throughly and avoiding touching your eyes, nose, and mouth. The CDC also recommends covering your cough or sneeze with a tissue and disinfecting objects and surfaces that are frequently touched.

The CDC does not recommend people wear face masks if they aren't sick. Face masks are only recommended for health workers, people showing symptoms of infection, and those who are taking care of a sick person in close settings.

The spread of this coronavirus has coincided with the typical flu season in the United States. The CDC recommends that people get a flu shot and take flu antiviral medication if prescribed, though neither will prevent or fight the coronavirus.

Work on a potential vaccine for this strain of coronavirus is underway, but officials from the Department of Health and Human Services and the CDC said it will be at least a year or a year and a half before a vaccine becomes available.

Creating a coronavirus vaccine is a challenging proposition, according to Agus.

"We've been trying to create a vaccine for the common cold — which is a coronavirus — for years."

Possible treatments for the virus, however, seem promising. According to Agus, several medicines are currently being tested on coronavirus patients around the world, including in the United States, with "encouraging" results.