SAN FRANCISCO - President Trump's announcement that he and Melania Trump tested positive for COVID-19 Friday has prompted a rush to do contact tracing.
"There's already a preliminary list of all the people that have been in contact with him and it's really, really long," said Dr. Monica Gandhi, a UCSF Professor, and expert in infectious diseases. Dr. Gandhi says the President's busy schedule and frequent decision to ignore CDC guidelines for masks and social distancing makes it a huge challenge.
"Usually citizens don't put so many people at risk, so this is really a concerning and going to be a long and messy effort to contact trace all these individuals," said Dr. Gandhi.
Experts say even though the President and First Lady get daily COVID-19 tests, that is not a preventative measure for stopping SARS-CoV2 coronavirus transmission.
"They could have been infectious for five days prior to actually developing symptoms," said Dr. Gandhi.
Five days ago, on Saturday, the President held a Rose Garden ceremony for Supreme Court Nominee Amy Coney Barrett.
Two Republican Senators on the Judiciary Committee, Senator Thom Tillis of North Carolina and Utah Senator Mike Lee both attended the outdoor event and both announced Friday that they tested positive for COVID-19.
They were among the crowd of people sitting shoulder to shoulder for the event. Many people were seen not wearing masks. Former Trump adviser Kellyanne Conway and University of Notre Dame President John Jenkins also attended and announced Friday they too tested positive.
RNC Chairwoman Ronna McDaniel is another Republican who tested positive for COVID-29 Friday, as well as at least one member of the white house press team.
There could be more.
The President traveled to three states in the past several days coming into contact with supporters in Ohio for the presidential debate Tuesday.
Then on Wednesday, the President met with people at a fundraiser in Minnesota Wednesday and a campaign rally in Duluth.
President Trump's close advisor Hope Hicks was sick on that campaign trip to Duluth and tested positive Thursday.
Despite the news, President Trump flew to another fundraiser Thursday in New Jersey, where the state now is doing contact tracing to find attendees.
Contact tracing has so far turned up no positives for Vice President and Karen Pence, Barron and Ivanka Trump, Jared Kushner, Mark Meadows, Kayleigh Mcenany, Mike Pompeo and Steven Mnuchin, who all tested negative Friday.
"Even if they've already tested negative, it's possible they could test positive tomorrow," said Susie Welty, a contact tracing expert at UCSF. Welty says that's because people can carry the virus before a test detects it.
"So by the time someone tests positive it's already too late," said Welty, noting that the President and the First Lady could have infected hundreds of people before testing positive, "in those 48 hours before he tested positive he was infectious, so anyone around him in those 48 hours has been exposed."
Jana Katsuyama is a reporter for KTVU. Email Jana at firstname.lastname@example.org and follow her on Twitter @JanaKTVU or Facebook @NewsJana