CDC says there is a lot it doesn’t know about how the COVID-19 virus might affect the country, but it wants the public to be prepared.

Officials at the Centers of Disease Control and Prevention say spread of the coronavirus in the U.S. is not a question of "if," but "when."

Dr. Nancy Messonnier, the CDC's director of the National Center for Immunization and Respiratory Diseases said the virus, called COVID-19, is "rapidly evolving and spreading" and that as more countries experience the spread of the coronavirus, "successful containment at U.S. borders is becoming problematic."

But Dr. Messonnier stressed that "our containment strategy has been largely successful."

“We have very few cases in the United States and no spread in the community,” Dr. Messonnier said

Community spread of the virus, which began its spread in China, have been reported in Hong Kong, Iran, Italy, Japan, Singapore, Korea, Taiwan and Thailand, Messonnier said in a Tuesday press conference. The behavior of the virus spread outside of China has raised concern in the U.S.

Ultimately the CDC expects the virus to spread in the U.S.

Houston Health Authority Dr. David Persse said that concern comes from the likely chance that someone infected with coronavirus will come to the U.S. and start spreading the virus before they can be identified and isolated.

He stressed that there is no need for people in the U.S. to panic.

“We are anticipating that that it is likely to occur at some point, hopefully it won’t, but we need to anticipate and behave as if it will at some point so we can take advantage of the time we have now and change our behaviors and protect ourselves should it occur that it spreads in the United States,” said Dr. Persse.

Dr. Persse said people must be vigilant about hygiene: washing hands, covering coughs, disinfecting surfaces, and staying home when sick.

“Those are the sorts of things that stop the progression of a virus throughout a community,” said Dr. Persse.

There is currently no vaccine to prevent the virus nor medication to treat it, but Messonnier said individuals and local communities should prepare for the possibility of an outbreak by implementing methods of "non-pharmaceutical intervention," or NPIs. She warned U.S citizens and local communities to prepare for "disruption to everyday life" in the case of a pandemic.

"We are asking the American public to work with us to prepare for the expectation that this is going to be bad," she said. Messonnier recounted a conversation she had with her children over breakfast, in which she discussed how her family would prepare for an outbreak. She said she called her local school superintendent with questions about schools' plans for dismissals, closures and teleschool.

Messonnier encouraged parents to do the same and prepare for how to handle childcare services if schools begin to close. She also recommended schools divide students into smaller groups or provide teleschooling services.

Other businesses can also prepare for an escalated outbreak of the coronavirus by replacing in-person meetings with teleconferences and increasing teleworking options, Messonnier said. Employees should also contact their supervisors for more information on those policies.

Communities should also prepare to "modify, postpone or cancel large gatherings," she said.

More than 80,000 people have been infected globally in the COVID-19 outbreak. More than 77,000 infections and more than 2,600 deaths have been reported in China.

South Korea now has the second most cases with 977. Health workers continue to find batches in the southeastern city of Daegu and nearby areas, where panic has brought towns to an eerie standstill.

In the U.S, 57 people have been infected. The CDC categorized these infections into separate categories: 14 have been infected in travel-related incidents and 43 infections were among individuals repatriated in the U.S. Of those 43, 3 infections were from individuals evacuated from Wuhan on charter flights and 40 cases were from individuals on the Diamond Princess Cruise Ship that was quarantined in Japan earlier this month.

Cambridge, Massachusetts based drugmaker Moderma announced this week it had sent its first batch of a possible coronavirus vaccine to the National Institutes of Health for early-stage testing.