The U.S. Centers for Disease Control and Prevention warned Tuesday that it expects the novel coronavirus to spread in the United States, cautioning Americans to expect "severe" disruptions to daily life.

"Ultimately, we expect we will see community spread in this country," said Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases.

"It's not so much a question of if this will happen anymore, but rather more a question of exactly when this will happen, and how many people in this country will have severe illness," she told reporters.

"We want to make sure the American public is prepared," she said.

COVID-19 has killed more than 2,600 people and infected almost 80,000 others, mainly in China. There are so far 53 recorded cases in the United States.

"Disruption to everyday life might be severe," Messonnier warned, saying that she is preparing her own family for the possibility of "significant disruption to our lives."

Messonnier advised business to consider offering remote working option to their employees and hospitals to explore expanding telehealth services. She also counseled parents to ask their children’s schools about closure plans.

The CDC is researching how it can stem the spread of the virus, including school closures, voluntary home quarantines and surface cleaning methods, Messonnier said.

In the absence of a vaccine or any form of treatment for COVID-19, so-called non pharmaceutical interventions "will be the most important tools in our response to this virus" she added.

These should be decided on a case-by-case basis depending on the severity of an outbreak within localities.

In a related development, the U.S. National Institutes of Health said Tuesday it had begun its first randomized clinical trial to investigate the safety and efficacy of the antiviral remdesivir in treating COVID-19.

The first trial participant is an American who was repatriated after being quarantined on the Diamond Princess cruise ship that docked in Yokohama, Japan and who is being treated at the University of Nebraska Medical Center in Omaha.

The trial's organizers said it will be adapted to enroll participants at other sites in the U.S. and worldwide, eventually including up to 400 people, and would also investigate other treatments.