Democratic presidential contenders Joe Biden and Bernie Sanders were left to reassess how to campaign in the face of a spreading US coronavirus outbreak on Wednesday, after the former vice president nearly swept a big day of nominating contests.
The two candidates canceled election night rallies on Tuesday, citing recommendations from public health officials to avoid assembling large indoor crowds.
Biden's campaign also canceled a Thursday get-out-the-vote event in Florida, which with Arizona, Illinois and Ohio will hold primary contests next week to nominate a Democratic challenger to Republican President Donald Trump in November.
Biden, the Democratic front-runner, said he would instead deliver on Thursday an address on the US coronavirus response in his hometown of Wilmington, Delaware.
"This is a matter, this whole coronavirus - is a matter of presidential leadership," Biden told reporters on Tuesday night in Philadelphia. "Later this week, I'll be speaking to you on what I believe the nation should be doing to address this virus."
COVID-19, the disease caused by the virus, is a highly contagious respiratory illness that has so far sickened almost 1,000 people in the United States and killed 29, mostly in Washington state.
The outbreak, which has infected more than 116,000 people and killed more than 4,000 worldwide, has shaken financial markets, forced school closures and prompted organizers to cancel concerts, conferences and sporting events.
Exit polls showed that primary voters on Tuesday regarded Biden as a better choice than Sanders to respond to the virus outbreak. In Washington, the state hit the hardest thus far, voters who said they were "very concerned" about it backed Biden over Sanders by a 2-to-1 margin.
Biden, a moderate, and Sanders, a self-described democratic socialist, have both criticized the Trump administration over its response to the outbreak. Their campaigns said on Tuesday they would consult with health officials about events going forward.
The Lawyers' Committee for Civil Rights Under Law urged state election officials to ensure that concerns about the virus did not interfere with upcoming votes.
"States must not wait a moment longer to take real steps to address the impact of the coronavirus on the 2020 election season," the committee said in a statement.
The Democratic National Committee said the next presidential debate, scheduled for Sunday in Arizona, would not have a live audience because of health concerns.