Dec. 31
The World Well being Group says that Chinese language well being officers in Wuhan revealed a “cluster of instances of pneumonia of unknown trigger.”
Jan. 8
The C.D.C. confirms the primary travel-related case of coronavirus in the USA: a person in Washington State.
Jan. 24
The C.D.C. says that it has developed a classy diagnostic take a look at and has sought F.D.A. permission to ship it to public labs across the nation.
Jan. 29
The White Home declares a coronavirus activity power led by the well being secretary, Alex M. Azar II. President Trump attends the group’s first assembly and tweets that the consultants “are on prime of it.”
Jan. 31
The Trump administration restricts journey from China, however exempts Individuals and permits commerce to proceed. Mr. Azar declares a public health emergency.
Early February
Stanford University develops its own test for the coronavirus but runs into regulatory roadblocks at the F.D.A.
Feb. 4
The F.D.A. approves the C.D.C. test, but the White House task force remains focused on the Diamond Princess cruise ship, which is placed under quarantine in Japan because 10 people on board are diagnosed with the coronavirus.
Feb. 12
The C.D.C. publicly discloses that its test kits aren’t working properly amid complaints from labs around the country that screening has been far too restricted.
Feb. 14
The C.D.C. announces that it will begin surveillance testing to track the virus. But a month later, it says it hopes to “begin rolling out” the program, which has yet to begin in a significant way.
Feb. 24
The chief executive of the Association of Public Health Laboratories writes to the F.D.A. that “we are now many weeks into the response with still no diagnostic or surveillance test available outside of C.D.C. for the vast majority of our member laboratories.” Separately, the head of the C.D.C. boasts to Congress about his agency’s “aggressive response” to screening.
Feb. 29
The F.D.A. relaxes its rules for some laboratories, allowing them to start testing before the agency has completed its approvals. At a White House news conference, Mr. Trump concedes there will be more cases, but says, “There’s no reason to panic at all.”
March 1
New York City reports its first case.