Coronavirus news: Fauci details lesser-publicized side effects of COVID-19

"A disturbing number of individuals" were found to have heart inflammation.

A pandemic of the novel coronavirus has now killed more than 973,000 people worldwide.

Over 31.7 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 6.9 million diagnosed cases and at least 201,617 deaths.

California has the most cases of any U.S. state, with more than 794,000 people diagnosed, according to Johns Hopkins data. California is followed by Texas and Florida, with over 741,000 cases and over 690,000 cases, respectively.

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

Missouri governor tests positive

Missouri Gov. Mike Parson and his wife Teresa tested positive for COVID-19 on Wednesday, his office said.

They were tested because Teresa had "minor symptoms," his office said. Gov. Parson has no symptoms.

"All official and campaign events have been canceled until further notice," the office said, adding that the governor's staff has been tested.

"Governor Parson continues to conduct and fulfill all roles of businesses of the state of Missouri from the Governor's Mansion," Parson's office said.

ABC News' Will Gretsky contributed to this report.

Indiana to lift nearly all restrictions

Indiana will move to Stage 5, its final phase of reopening, on Saturday, Gov. Eric Holcomb has announced.

Retail stores, malls, restaurants, bars and nightclubs can operate at full capacity under the Stage 5 rules.

There will be no restrictions at gyms and large events like sports, fairs and festivals can resume.

Restrictions will also be lifted at amusement parks and water parks, though people are advised to maintain social distancing.

Masks will still be required.

ABC News' Will Gretsky contributed to this report.

France announces new restrictions as cases rise

New restrictions are coming in France as the nation deals with the highest increase of COVID-19 cases in Europe since May.

French Health Minister Olivier Véran announced a set of targeted restrictions Wednesday to be implemented in various cities for two weeks.

Starting Saturday, in Paris and seven other major cities, parties will be prohibited, with outdoor gatherings limited to 10 people.

Bars must shut their doors at 10 p.m., gyms will be closed and sporting events will be limited to 1,000 spectators.

Meanwhile, Marseille and Guadeloupe are enacting stricter rules; starting Monday all bars and restaurants will be closed.

French officials reported 13,072 new cases on Wednesday, just short of the highest daily record of 13,215. France now has over 481,000 COVID-19 cases and at least 31,459 fatalities.

ABC News' Ibtissem Guenfoud and Christine Theodorou contributed to this report.

20 times more likely to catch COVID-19 indoors than outdoors: Study

Dr. Blythe Adamson, a former member of the White House coronavirus task force, told "GMA3" on Wednesday, "One of things that we just learned recently -- and published in a new study today in Clinical and Infectious Diseases -- is that being indoors, you're 20 times more likely to catch COVID from an infectious person than if you were around them outdoors."

Adamson is now adviser to Testing for America, a nonprofit established to help solve the testing crisis.

Adamson stressed that the U.S. must "be flexible and adapt, so as we learn more about the science, we're willing to change our public policies so that they match the best science."

"There's a lot of work for us to continue to do over the next couple of months. As we move forward into flu season, it's even more important that we're able to distinguish between a viral infection that's from influenza or coronavirus," she said.