Five senior US Republicans have quarantined themselves after coming into contact with a person who tested positive for coronavirus.
The members of Congress, who include Texas Senator Ted Cruz, self-isolated after they shook hands with an infected individual at a conference.
President Donald Trump, who was also at the event last month, insists he is in good health and has not taken a test.
One Democrat has also self-isolated after she met someone with the virus.
There are more than 700 confirmed cases in the US and 26 people have died so far.
Mr Cruz, Arizona Congressman Paul Gosar, Georgia Congressman Doug Collins and Florida Congressman Matt Gaetz are all self-quarantining for the recommended 14-days after they met the same infected person at CPAC, a conservative political conference, at the end of February.
Republican Representative Mark Meadows, President Donald Trump’s newly appointed chief of staff, also met the person and is in self-quarantine. He is not exhibiting any symptoms and a precautionary test came back negative, a spokesman said.
Mr Trump and Vice-President Mike Pence attended the same event in Maryland but neither of them interacted with the individual. Mr Trump did shake hands with the conference chairman who had had contact with the patient.
But, on Monday, the White House announced that Mr Trump had not been tested for the virus. “He has neither had prolonged close contact with any known confirmed Covid-19 patients, nor does he have any symptoms,” a spokeswoman said.
“President Trump remains in excellent health, and his physician will continue to closely monitor him,” she added.
The vice-president, who also confirmed he had not been tested for the virus, said the administration was consulting Congress on providing paid sick leave to workers.