(CNN) - Former Vice President Joe Biden will win the Illinois and Florida Democratic primaries, CNN projects, victories that will allow him to substantially expand his delegate lead over Vermont Sen. Bernie Sanders as they vie for the Democratic nomination.

Florida, Illinois and Arizona were the three states where voters headed to the polls Tuesday amid the coronavirus pandemic. Tuesday's primaries come at a time when state and local officials are clearly conflicted about the ethics of asking Americans to leave their homes as many are anxious and self-isolating in an effort to slow the spread of novel coronavirus.

Biden had led in polls in both Illinois and Florida, where the most delegates are at stake on Tuesday. In Florida, Biden posted huge double-digit leads after his streak of victories in South Carolina and the two Super Tuesday contests. As the delegates piled up for Biden on Tuesday night, CNN estimated that the former vice president would need to win 47% of the remaining delegates in order to win, while Sanders must win 57.9% of the remaining delegates to clinch the nomination -- a near mathematical impossibility.

Last week, Biden led Sanders 66% to 22% in a University of North Florida poll -- showing his potential to increase his count in the delegate-rich state.

Amid anecdotal reports of low turnout and hand sanitizer shortages, Tuesday's contests unfolded under a cloud of uncertainty at the same time that the number of reported coronavirus cases continued to grow by hundreds every hour.

In addition to Florida and Illinois, Biden is heavily favored over Sanders and Arizona, a pattern that has been largely unchanged since he began his comeback in South Carolina on February 29 and then notched victories in 15 states over the two Super Tuesday contests.