Coronavirus latest: 94% of COVID deaths in US had underlying conditions, CDC says

The novel coronavirus has infected more than 25 million people worldwide.

A pandemic of the novel coronavirus has now killed more than 847,000 people worldwide.

Over 25.3 million people across the globe have been diagnosed with COVID-19, the disease caused by the new respiratory virus, according to data compiled by the Center for Systems Science and Engineering at Johns Hopkins University. The criteria for diagnosis -- through clinical means or a lab test -- has varied from country-to-country. Still, the actual numbers are believed to be much higher due to testing shortages, many unreported cases and suspicions that some national governments are hiding or downplaying the scope of their outbreaks.

The United States is the worst-affected country, with more than 6 million diagnosed cases and at least 183,399 deaths.

California has the most coronavirus cases in the U.S., with more than 708,000 people diagnosed, according to Johns Hopkins data. California is followed by Texas and Florida, with over 630,000 cases and over 623,000 cases respectively.

Nearly 170 vaccine candidates for COVID-19 are being tracked by the World Health Organization, six of which are in crucial phase three trials.

Delta, American join United in permanently eliminating change fees

Delta Airlines and American Airlines are joining United in eliminating change fees -- a practice established during the pandemic.

Delta's no change fee policy is effective immediately. It applies to tickets within the U.S. as well as Puerto Rico and the U.S. Virgin Islands. The policy doesn't apply to basic economy tickets, Delta said.

American Airlines said change fees are eliminated for all U.S. flights as well as "short-haul international" flights. The policy applies to premium cabin fares and "most Main Cabin fares," the airline said.

On Sunday, United said it was immediately dropping change fees on all standard economy and premium cabin tickets for U.S. travel.

ABC News' Gio Benitez and Mina Kaji contributed to this report.

New York sees lowest single-day death toll so far

In New York -- which was the U.S. epicenter of the pandemic in March and April -- one person was reported dead from the coronavirus on Sunday, the state's lowest daily death toll so far.

"One New Yorker passed away and that New Yorker's family is in our thoughts and prayers, but we should pause a moment on that fact. There was a time when we were going through this crisis when we literally had hundreds of people dying every day," Gov. Andrew Cuomo said in a statement on Monday. "Together we did flatten the curve and we saved lives."

Hospitalizations and ICU patients also reached record lows. New York's number of COVID-19 hospitalizations has fallen to 418 -- the lowest since March 16 -- and the state's number of ICU patients has dropped to 109, the lowest since March 15, Cuomo said Monday.

Of those tested across the state on Sunday, less than 1% were positive, the governor said.

New York has the fourth-highest number of coronavirus cases in the U.S., with more than 434,000 people diagnosed, according to the state.

At least 25,328 people in New York have died.

California coronavirus cases climb over 700,000

The number of people in California diagnosed with the coronavirus climbed over 700,000 on Monday, according to data from the state's Department of Health.

With at least 704,085 confirmed cases, California has more coronavirus cases than any other state in the U.S.

Of those tested across the state in the last two weeks, 5.3% were positive for the virus, according to the state.

California's death toll stands at 12,933.

ABC News' Matt Fuhrman contributed to this report.

USDA extends school meal waivers through Dec. 31

The United States Department of Agriculture (USDA) has extended waivers allowing the distribution of meals to students outside of physical schools due to the pandemic through Dec. 31. This follows calls from school officials and anti-hunger groups who were concerned some students would go hungry if they continued with virtual-only learning.

But the USDA has not extended the waivers passed Dec. 31, saying Congress has not appropriated money to fund the additional cost to the programs.

"While there have been some well-meaning people asking USDA to fund this through the entire 2020-2021 school year, we are obligated to not spend more than is appropriated by Congress," the USDA said in a press release.

Congress also has not extended the Pandemic EBT program which gave families monetary benefits to cover the cost of meals children would have eaten at school, in some cases directly loaded onto their SNAP cards. The program has been lauded as the most sustainable way to help families struggling financially because they can buy food for themselves and spend at retailers in their area.

ABC News' Stephanie Ebbs contributed to this report.