Since the first U.S. case of the coronavirus was identified in Washington state on January 21, health officials have identified thousands of cases across the U.S. By March 16, the virus had expanded its presence from several isolated clusters in Washington, New York, and California to 49 states and the District of Columbia. To date, there have been over 70 deaths across the country.

Social distancing is widely seen as the best available means to “flatten the curve of the pandemic,” a phrase epidemiologists use to describe slowing the spread of infection. This approach can save lives by keeping local health care systems from being overwhelmed.

In response to mounting cases, states have begun closing schools, banning large gatherings, and urging people to stay home when possible. On Monday, President Trump announced new guidelines recommending Americans avoid gathering in groups of more than 10 people, discretionary travel, and going out to eat.

To avoid spreading the disease, the CDC also recommends basic precautions like hand washing and cleaning frequently touched surfaces every day.

Globally, the respiratory disease has spread to dozens of countries and killed several thousand people since it was first reported in Wuhan, China in December.

Warnings issued by the CDC recommend avoiding nonessential travel to dozens of countries with outbreaks of COVID-19, including China, Iran, South Korea, and much of Europe. The government has banned travel from Europe, although the ban makes exceptions, including for American citizens and legal permanent residents.

Follow NPR’s ongoing coronavirus coverage.