US Secretary of State Antony Blinken tested negative for Covid-19 on Monday morning, the State Department said, after department spokesman Ned Price tested positive and went into quarantine.
“After experiencing symptoms for the first time this morning, I tested positive for Covid-19 shortly thereafter, and will now quarantine for the next 10 days,” Mr Price, who has been vaccinated, said on Twitter.
“I'm feeling under the weather but am grateful for the protection from severe illness offered by safe and effective vaccines.”
Mr Price attended more than half a dozen meetings with Mr Blinken last week in New York on the sidelines of the UN General Assembly, including with senior officials from Brazil, Britain, Turkey and the EU. He also briefed reporters regularly at the Palace Hotel.
Mr Price's diagnosis is the highest-profile Covid-19 case for an official in the Biden administration. Several members of former president Donald Trump's administration, and Mr Trump himself, caught the virus.
In a regular briefing with reporters conducted by phone on Monday, department deputy spokeswoman Jalina Porter said Mr Blinken had tested negative as recently as Monday morning and none of the other members of the travelling party were currently exhibiting symptoms.
Asked if the department had notified foreign delegations that met Mr Price last week, Ms Porter said officials had consulted with the State Department's medical unit and concluded only those who had contact with Mr Price from Saturday onward were at risk of exposure.
“I just do want to underscore that spokesperson Price hasn't been in contact with any foreign delegations since Thursday, which is nearly 100 hours before he actually started to experience any symptoms,” Ms Porter said, and added that Mr Price had not been with Mr Blinken or other State Department officials on Saturday or since then.
The State Department did not have any details on where Mr Price had contracted the virus, she said.
Mr Price spent a good part of last week within Mr Blinken's close circle, which included Deputy Secretary Wendy Sherman and Undersecretary for Political Affairs Victoria Nuland, who held their own separate meetings with a number of foreign delegations.
Critics of the Biden administration who oppose a vaccination mandate used Mr Price’s diagnosis to defend their position.
“Fully vaccinated Ned Price has been spreading covid with a breakthrough case. But folks with natural immunity are still discriminated against," tweeted David Asman, a conservative writer.
But the US Centres of Disease Control and Prevention stressed that “fully vaccinated people with a vaccine breakthrough infection are less likely to develop serious illness than those who are unvaccinated and get Covid-19."