During an online question-and-answer session with Warriors guard Stephen Curry on Thursday morning, Dr. Anthony Fauci made one thing clear: The coronavirus crisis should not be taken lightly.

Asked whether people were overreacting about the spread of the respiratory disease, Fauci — the director of the National Institute of Allergy and Infectious Diseases — didn’t mince words, saying, “This is serious business.”

For nearly 30 minutes on an Instagram live feed, Curry asked Fauci the questions that many people stuck indoors have wondered: When will they be able to attend large gatherings again? When should someone get tested for the coronavirus? Is it possible to get the respiratory disease twice? What is the latest on a vaccine?

It was apparent that Curry had thoroughly researched the topic. Roughly a half-dozen times during the conversation, Fauci — a leading expert on the coronavirus pandemic and a member of the White House Coronavirus Task Force — lauded Curry for his detailed line of questioning.

After seeing numerous pictures online in recent days of young people not practicing social distancing, Curry had his close friend and business partner Bryant Barr set up a chat with Fauci. Thursday’s conversation drew nearly 50,000 viewers across the world. Among those who logged on were former President Barack Obama, Justin Bieber, the rapper Common and Heat forward Andre Iguodala, with Bieber, Common and Iguodala even asking questions.

Midway through the Q and A, Curry said publicly for the first time that he was tested for the coronavirus when he came down with the flu a week before the NBA suspended play. This makes Curry the only Golden State player known to have been tested. During a conference call with reporters last week, general manager Bob Myers said that asymptomatic players weren’t being tested because of a lack of test kits in California.

Even now, as commercial businesses have made tests more available, Fauci encourages people to call a healthcare provider to see whether a test is necessary. If someone believes he or she has the coronavirus, he or she should stay self-quarantined at home until the symptoms progress.

“The bigger issue is don’t flood the emergency rooms,” Fauci said. “Stay at home. If you really are seriously ill, then you’ve got to go quickly there. But if you have aches, pains and a fever, stay where you are, and contact a physician.”

Fauci is optimistic that a vaccine will be available in time for flu season next winter. In the meantime, he is stressing that social distancing is the only way to lower the number of cases in the U.S. and, eventually, allow government officials to lessen shelter-in-place orders.

As of Thursday afternoon, the U.S. had recorded 80,857 total cases, second only to China’s 81,285. California’s 2,982 cases were second among U.S. states to New York’s 32,966.

The U.S.’s 13,653 “new” cases are more than double those of any other country, according to Centers for Disease Control and Prevention.

“What you need is you need to see the trajectory of the curve start to come down,” Fauci said. “We see that in China. They went up and down. They’re starting to get back to some normal life. They’ve got to be careful to make sure they don’t reintroduce the virus back into China. They’re on the other end of the curve.

“We could start thinking about getting back to some degree of normality when the (U.S.) as a whole has turned that corner and started coming down. Then you can deal with cases much more easily than getting overwhelmed by cases, which is what’s going on in New York City.”

Thursday’s conversation with Fauci was just the latest example of Curry using his massive social-media platform — he has 14.2 million Twitter followers and 29.8 million Instagram followers — to bring awareness about the coronavirus crisis. He has done a PSA on the disease that gained significant traction online.

In addition to pledging one million meals through his Eat. Learn. Play. Foundation to underprivileged Alameda County children who depend on school meals, Curry has donated to the $1 million sum meant to cover wages Warriors part-time employees are expected to lose with the NBA season suspended.

“When anybody’s life is interrupted, whether you’ve been affected personally or not, there’s a level of comfort that what we’re doing is in the right spirit of trying to stop the spread as fast as possible,” Curry said Thursday, wrapping up his Instagram live. “We want people to return to their normal lives understanding that there is a strategy to doing that, and that we all have to adhere to it.”

Connor Letourneau covers the Warriors for The San Francisco Chronicle. Email: cletourneau@sfchronicle.com Twitter: @Con_Chron