CLEVELAND, Ohio—Major concerns about the coronavirus have made it to the 2020 campaign trail.

The campaigns of both Sen. Bernie Sanders (I-VT) and former Vice President Joe Biden have canceled their planned rallies here Tuesday night as concerns over the spread of the novel coronavirus continue, with the Sanders campaign saying the fate of future campaign events will be decided “on a case by case basis.”

The decision comes as a series of non-political events around the country have been postponed or canceled in an effort to prevent the virus from spreading further.

“We are heeding the public warnings from Ohio state officials, who have communicated concern about holding large, indoor events during the coronavirus outbreak,” Sanders spokesman Mike Casca said in an email. “Sen. Sanders would like to express his regret to the thousands of Ohioans who had planned to attend the event tonight.”

A source close to the Biden campaign said the decision to cancel the rally came just after Sanders’ announcement.

“In accordance with guidance from public officials and out of an abundance of caution, our rally in Cleveland, Ohio tonight is canceled,” Biden campaign spokesperson Kate Bedingfield said in a statement after The Daily Beast broke news of the rally’s cancellation. “We will continue to consult with public health officials and public health guidance and make announcements about future events in the coming days.”

Future Biden fundraisers may soon be moved entirely online to prevent the spread of the virus, a source close to the campaign told The Daily Beast. The decision to change fundraisers into strictly digital gatherings, the source said, will be made on Wednesday. Asked earlier this week about the rumored postponement of in-person fundraisers, a Biden campaign spokesperson told The Daily Beast that the 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.”

The cancellations came amid voting in six states Tuesday night and hours after Ohio Governor Mike DeWine declared a state of emergency following the news that three people in Cuyahoga County, where Cleveland is located, had tested positive for the COVID-19 virus.

DeWine did not say that the rallies should be canceled, according to the Dayton Daily News.

“I will simply say that a gathering of a lot of people is probably not a great idea,” DeWine said at a news conference on Tuesday afternoon. "They have a right to do it as the First Amendment.”

Ohio is one of four states that will hold their primary on March 17. Florida, Illinois, and Arizona will also hold contests—a Democratic debate is scheduled for Sunday night in Phoenix.

Until Tuesday, there was little visible evidence on the campaign trail that the coronavirus had curtailed candidates efforts, save hand sanitizer bottles or aides offering Purell as people filed into the events.