Former vice president Joe Biden said Thursday that the coronavirus outbreak has revealed the Trump administration’s “severe shortcomings” as he delivered remarks on a subject that has rapidly come to dominate and reshape the Democratic campaign for the White House.

Sen. Bernie Sanders (I-Vt.) also delivered remarks on the health and economic effects of the outbreak, comparing it in scale to a major war. Later Thursday afternoon, Sanders’s campaign was given a boost when he was declared the winner of last week’s Super Tuesday contest in California.

Also Thursday, the Democratic National Committee announced that it was moving a one-on-one debate Sunday between Biden and Sanders from Arizona to a television studio in the nation’s capital “out of an abundance of caution” amid the outbreak.

Biden and Sanders will go before the voters again Tuesday in Arizona, Florida, Illinois and Ohio — contests in which Biden hopes to add to his delegate lead and put the race out of reach for Sanders. As he turns his attention toward President Trump, Biden is also replacing his campaign manager.