Early missteps allowed the new coronavirus to spread throughout the U.S for weeks before state and local officials implemented strict lockdowns designed to keep the pandemic from spinning further out of control.

Why it matters: The U.S. missed the boat on the kind of swift, early response that would have been most effective, and has been scrambling to catch up ever since. This timeline, compiled from official sources as well as media reports, shows how that all-important time was lost.

Dec. 31, 2019: China reports the novel coronavirus to the World Health Organization.

Jan. 6: The Centers for Disease Control and Prevention issued a travel notice for Wuhan, China.

Jan. 15: The first U.S. case is confirmed, in a man who traveled from Wuhan.

Jan. 17: The World Health Organization publishes a protocol for manufacturing coronavirus tests.

The Centers for Disease Control and Prevention opts to develop its own test instead of using the WHO's.

Jan. 30: The WHO declares global health emergency.

The CDC confirms person-to-person spread of COVID-19 within the U.S.

Jan. 31: The Trump Administration suspended entry into the U.S. for most foreign nationals who had traveled to China in the past 14 days.

The WHO reports 11,950 coronavirus cases worldwide.

Feb. 5: The CDC begins shipping its diagnostic tests to state and local health agencies.

Feb. 8: Labs report problems with the CDC’s tests.

Feb. 24: President Trump tweets: “The Coronavirus is very much under control in the USA. We are in contact with everyone and all relevant countries. CDC & World Health have been working hard and very smart. Stock Market starting to look very good to me!”

Feb. 29: Washington state reports the first COVID-19 death in the U.S.

The Food and Drug Administration allows academic labs to develop and begin testing coronavirus testing kits while reviewing pending applications.

The WHO reports 86,604 coronavirus cases worldwide.

March 5: LabCorp and Quest Diagnostics launch coronavirus test for commercial use.

March 9: Trump tweets: “So last year 37,000 Americans died from the common Flu. It averages between 27,000 and 70,000 per year. Nothing is shut down, life & the economy go on. At this moment there are 546 confirmed cases of CoronaVirus, with 22 deaths. Think about that!”

The WHO reports 114,381 coronavirus cases worldwide.

March 13: Trump declares a national emergency, freeing up $50 billion in federal funds for states and territories.

March 15: 33 states and the District of Columbia closed public schools, according to Education Week. This included the New York City school system, the largest in the country.

March 16: Trump advises Americans to self-isolate for 15 days.

March 19: Trump signed into law an emergency coronavirus relief package for paid sick leave and free testing.

March 23: 9 states had stay-at-home orders.

Washington, Oregon, California, Louisiana, Illinois, Ohio, New York, Massachusetts and New Jersey.

March 26: The U.S. now leads world in coronavirus cases.

12 more states issue stay-at-home orders, totaling 21: Idaho, Colorado, New Mexico, Michigan, Wisconsin, Kentucky, Indiana, West Virginia, Hawaii, Connecticut, Vermont and Delaware

March 29: Trump extends social distancing measures to April 30.

March 30: Nine more states issue stay-at-home orders, bringing the total to 30.

Governors say testing is still lacking in many states.

March 31: Trump warns of the potential for 100,000 to 240,000 deaths.

April 6: Twelve more states issue stay-at-home orders, bringing the total to 42.