With Americans forced to self-isolate in their homes amid the coronavirus pandemic, turnout has been noticeably low in parts of Illinois, one of the three states holding presidential primaries on Tuesday.

For comparison: Turnout in Chicago by early afternoon was less than half the level from the 2016 Democratic presidential primary, according to the city’s board of elections.

CORONAVIRUS PANDEMIC THREATENS TO UPEND REMAINING PRIMARIES, CONVENTIONS

But election officials in Illinois, as well as in Arizona and Florida, the other two states holding primaries on Tuesday, were confident that a surge in early voting and mail-in ballots could make up for the drop in voting on primary day.

In recent days, election officials in all three states relocated some polling stations that were originally set to be located in senior centers or nursing homes. Senior citizens are most at risk from the coronavirus, which is officially known as COVID-19.

Concerns about the outbreak likely caused some poll workers in Florida and Illinois to stay home on Tuesday.

The relocating of polling sites in Florida led to some disruptions, and low turnout was reported in some counties while voting was going smoothly in other locations. There were no major issues reported by early afternoon in Arizona – where most voters had cast their ballots before primary day.

Most polls in Florida were set to close at 7 p.m. ET, with the western part of the state’s panhandle – which is located in the central time zone -- closing at 8 p.m. ET. Polls in Illinois were set to close at 8 p.m. ET and polls in Arizona were scheduled to shut down at 10 p.m. ET.

On primary eve, Ohio’s governor used an emergency order to postpone his state’s contest after the Centers for Disease Control and Prevention (CDC) urged against any gatherings nationwide of 50 people or more.

“We cannot conduct this election tomorrow,” Gov. Mike DeWine stressed.

Mailing it in

In an effort to keep voters and poll workers safe amid the coronavirus pandemic and prevent the postponement of primaries, the Democratic National Committee is calling on states that have upcoming presidential primary contests to offer options like voting by mail.

“States can provide easy access to voting while still taking necessary precautions to protect the health and safety of the American people. In order to ensure the voices of voters are heard, the DNC is urging the remaining primary states to use a variety of other critical mechanisms that will make voting easier and safer for voters and election officials alike,” DNC chair Tom Perez urged in a Tuesday statement.

Team Biden confident

Former Vice President Joe Biden’s campaign is touting the early voter turnout.

“While voter turnout on Election Day itself may be lower due to COVID-19 concerns, we believe that, with early vote and vote by mail, overall turnout will be roughly on pace for 2016 in Arizona and Florida and roughly on pace for 2018 in Illinois, and that voter turnout in all three states will reflect the population at large,” Biden deputy campaign manager Kate Bedingfield highlighted in a memo sent to reporters on Tuesday afternoon.

The campaign spotlighted the high numbers of older voters – and voters of color – who were casting ballots in all three states. The former vice president enjoyed strong support from older voters and African Americans, while his rival for the Democratic presidential nomination – Sen. Bernie Sanders of Vermont – has struggled to resonate with such voters.

PRIMARIES GO AHEAD IN THREE STATES AS BIDEN ATTEMPS TO SHUT OUT SANDERS

Sanders – a progressive champion who’s making his second straight White House run -- was the front-runner in the race for much of February thanks to a partial victory in Iowa’s caucuses, an outright win in New Hampshire’s primary, and a shellacking of the rest of the Democratic field of contenders in Nevada’s caucuses.

But over the last two and a half weeks, Sanders has watched Joe Biden zoom past him in the race for the presidential nomination. Following a landslide win in South Carolina’s primary and sweeping victories in the coast-to-coast Super Tuesday states as well as last week’s mini Super Tuesday, the former vice president cemented his position as the unrivaled front-runner and has taken a commanding lead over Sanders in the all-important race for convention delegates.

The Biden campaign – in its memo – said, “We expect to emerge tonight with a bigger delegate lead than we had going into the night.”

And they argued, “It would take a drastic, historically-incomparable swing for Senator Sanders to win more delegates than Biden today or to close the delegate differential.”

'This primary is far from over'

Pre-primary public opinion polls indicated Biden enjoying large leads in all three states. And if Tuesday’s contests deliver another round of decisive victories by the former vice president, the chorus of calls for Sanders to step aside will grow louder.

But Biden will still be short of the 1,991 pledged delegates needed to clinch the nomination. And with the primary calendar likely grinding to a halt after Tuesday's contests due to the coronavirus pandemic, there’s the possibility that Sanders could stay alive in a race that will be frozen in time.

On Monday, Sanders didn’t sound like a candidate ready to call it quits.

“This primary is far from over,” Sanders stressed in an email to supporters on the eve of Tuesday’s contests.

And on Tuesday, the Sanders campaign spotlighted that three virtual campaign events they held the past three days “amassed 5.3 million views in total.”

“Our digital organizing infrastructure is unmatched,” Sanders campaign manager Faiz Shakir emphasized.

And the Sanders campaign was also spotlighting on Tuesday its hands-off approach to trying to get their supporters to the polls – and emphasizing that health concerns take precedent.

“We are not doing traditional GOTV outreach in states holding primary contests today. We are making clear to voters that we believe going to the polls amid the coronavirus outbreak is a personal decision and we respect whichever choice they make. We are also passing along guidance from the CDC on staying safe during the crisis,” Sanders communications director Mike Casca said in a statement.

Fox News' Andrew O'Reilly, Allie Raffa, and Andrew Craft contributed to this report.