Amid growing coronavirus fears, some 2020 candidates alter campaign methods An upcoming Catholics for Trump event in Milwaukee has been canceled.

Amid the ongoing novel coronavirus threat and fears of the virus spreading in the U.S., former Vice President Joe Biden's campaign has announced it will be hosting “virtual events” in place of events on the ground in Illinois and Florida.

"We have been and will continue to consult with relevant officials, including our recently announced Public Health Advisory Committee, regarding steps the campaign should take to minimize health risks for staff and supporters," Biden's campaign said in a statement on Wednesday. “As a result of those conversations and at the request of elected officials in Illinois and Florida, we will no longer hold large crowd events on Friday and Monday in those states."

Both Biden and his rival for the Democratic presidential nomination, Vermont Sen. Bernie Sanders, canceled rallies in Cleveland, Ohio Tuesday night amid the novel coronavirus spread in the U.S.

The moves come as President Donald Trump and the 2020 Democratic presidential front-runners continue to campaign amid what has now been declared a pandemic by the World Health Organization.

Trump campaign national press secretary Kayleigh McEnany sought to defend continuing to hold rallies amid the surging coronavirus outbreak in an interview on FOX Business Network earlier on Wednesday. She cited Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, in her defense saying the top expert had said to "take it case by case," and because of that advice they were proceeding as normal.

Fauci had just testified on Capitol Hill that he recommends "there not be large crowds...as a public health official, anything that has large crowds is something that would give a risk to spread.”

Host Stuart Varney pushed back on McEnany, raising Fauci's new recommendations.

"Look, the president is the best authority on this issue," McEnany said. "He takes into consult the words of everyone around him that would include Alex Azar, that would include Dr. Fauci, that would include others. I will leave it to the president."

Trump campaign communications director Tim Murtaugh told ABC News on Saturday that they were "proceeding as normal" with the reelection events, though Trump currently has no rallies on his public schedule. But in the last week, states like Washington, New York and California have all declared a state of emergency and other events with large gatherings -- like South by Southwest -- are being canceled across the country.

Wednesday evening, during an Oval Office address, Trump emphasized making the effort to specifically protect older Americans by avoiding non-essential travel in crowded areas and avoiding all medically unnecessary trips to nursing homes.

Following the White House's lead, the Trump campaign announced on Twitter it is "postponing" next week's Catholics for Trump event in Milwaukee that was set to feature President Trump.

The event was announced only just over 24 hours ago amid heightened concerns over the coronavirus outbreak.

The Trump campaign had previously declined to comment when asked if they plan to take any precautions at the Wisconsin event which was to take place in a state impacted by the outbreak with three known cases so far. Biden rally goers were given hand sanitizer at a rally in Detroit on Monday.

While this wasn't the Keep America Great rally announcement that campaign sources have previously said was coming, it was a large scale coalition rollout similar to what the campaign has done with "Evangelicals for Trump."

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The Trump campaign has held discussions about what to do if the rallies have to be put on hold, which currently isn’t the plan, two campaign sources told ABC News.

Currently, the number of Americans diagnosed with the novel coronavirus is now more than 1,000, according to a case count by Johns Hopkins University. At least 36 people have died in the U.S..

On Friday, the White House imposed new guest restrictions, including checking where guests have traveled recently.

Some of the procedures are standard, including increased cleaning of high-traffic areas and educating staff on best hygiene practices and sick leave policies.

The president has previously defended holding rallies amid the crisis, including at a visit to the Centers for Disease Control and Prevention in Atlanta on Friday, saying his rallies continue to thrive, even as more cases of coronavirus in the U.S. arise.

"I tell you what, I haven't had any problem filling them," he said of recent rallies. "It doesn't bother them and it doesn't bother me."

Last Monday, when Trump was asked if he thinks it’s safe to hold big rallies as the virus spreads he said, “I think it's very safe."

"I think it's very safe," he said. "These were set up a long time ago."

He also pointed out that the Democratic contenders too were still "all having rallies."

However, the president's Democratic rivals seem to be altering their campaigning methods amid their intensifying and winnowing primary.

Both Sanders and Biden have held events in recent days and have had rallies.

On Saturday, Biden held a rally in Missouri with more than 2,300 people in attendance-- the former vice president has drawn some of the biggest crowds of his campaign in the past few days.

While Biden has generally spent an extended period of time of the rope line following his events throughout his 2020 campaign, over the weekend, Biden spent very little time interacting with voters following his remarks at events -- a change his campaign seemed to attribute to concerns about coronavirus.

"The Biden campaign will continue to closely follow guidance offered by federal and local public health officials on the types of events we hold and how we execute them. In contrast with our current president, who not only doesn’t amplify the guidance that the experts offer -- but directly contradicts it -- Vice President Biden and our team will lead by example in following expert advice and complying with reasonable risk mitigations. At the same time, we will continue to run an aggressive, national campaign to win the Democratic nomination and defeat Donald Trump," the Biden campaign said in a statement.

Biden too commented on how his campaign was adapting to the growing concerns about the virus, reiterating their reliance on guidance from the CDC.

"We’re listening to the experts and the CDC, and taking advice from them. Whatever advice they give me, we’ll take," Biden told reporters Sunday afternoon.

Sanders has indicated that coronavirus is being considered as the campaign plans large rallies and noted that the campaign has checked in with public health officials in Los Angeles and San Jose, Calif., prior to rallies. The Sanders campaign didn't indicate any plans to change its upcoming schedule, with a campaign official telling ABC News, “We continue to be in direct contact with local health officials.”

Sanders hosted a roundtable with medical professionals in Detroit on Monday to discuss the coronavirus.

The Trump campaign has postponed its "Women for Trump" bus tour that was set to kick off Monday in Michigan featuring top surrogates including Mercedes Schlapp, whose husband is the CPAC chairman-- a conservative conference where at least one attendee has tested positive for the coronavirus, the Trump campaign confirmed to ABC News.

ABC News' Molly Nagle, Katherine Faulders, Averi Harper and Johnny Verhovek and Lauren Lantry contributed to this report.