Party hosts planning boisterous New Year’s Eve soirees last December had an almost too obvious theme at the ready: the roaring twenties.

Dress to the nines like flappers and swells, cut a rug to Fats Waller’s “Ain’t Misbehavin,” and make believe you’re in a carefree Jazz Age where the party might never stop.

Except it did, almost immediately. So far, the 2020s have been anything but roaring. The coronavirus brought nightlife to an immediate halt, making the idea of frivolous fun seem like a cruel, long-gone memory.

But here’s another thing about the age of the Great Gatsby, the Harlem Renaissance, and bathtub gin: It followed the flu pandemic of 1918. That global crisis claimed 675,000 American lives and an unfathomable 50 million worldwide, according to the Centers for Disease Control and Prevention.

So while our lives remain socially distanced and COVID-19 precautions forbid crowds at music venues and sporting events, does history suggest that when public life returns, it’ll come back with a joyous explosion of pent-up energy?

Will the 2020s roar, after all?

Maybe so, but not anytime soon.

“There will be that dynamic of, as soon as something seems reasonably safe, a subset of people who will flock to it,” says Kathleen Bachynski, professor of public health at Muhlenberg College.

“Which is completely understandable in terms of the fun and pleasure of large gatherings. ... We all want to be able to get back to that.”

But right now, six months after the shutdown began, the timetable for commingling in a crowded club or even an outdoor music festival remains uncertain.

“It’s not like a vaccine will show up and — boom! — overnight we’re suddenly able to do everything again as if COVID-19 had never existed,” Bachynski says.

As the pandemic drags on, “post-COVID” has become chimerical. But there are hopes that live music will revive this spring in a way that feels both safe and fun. “I think we’ll see a lot of outdoor shows with lower capacity when we can go outside again,” says Dave Pianka, the DJ and promoter who has been staging Making Time parties in Philadelphia since 2000.

“Some people are dying to go to venues and are going to go no matter what,” Pianka says. “But people are fearful as well.”

Look around and there’s evidence for a yearning to rock out again. Drive-in concerts, which offer a compromise in the live music experience, have sold out quickly.

Music fan Amy Munz went to 125 shows last year with her husband, Bill. “Once the world opens up again, we plan on keeping that same pace of two or three shows a week,” if not increasing it, she said. “So many great bands tour through our city!”

But will fans also crave the virtual connections they’ve developed with performers during lockdown? Billboard reported this month that livestreaming has grown into a billion-dollar industry.

Pianka thinks so. He’s learned to connect virtually — on Oct. 2 he’s staging a 36-hour Making Time streaming festival with Hot Chip and other DJs from around the world performing as holograms — and he thinks the future lies in live performances that are also streamed.

With smaller-capacity shows post-COVID-19, “artists are going to get paid less than they used to," he says. "To balance that, you livestream the show. You can reach people in places a tour will never get to.”

“Those who spiritually reconnected with themselves during COVID will be pioneers in the new world of doing things,” agrees King Britt, the Philadelphia DJ and producer who teaches a course called Blacktronika: Afrofuturism in Electronic Music at the University of California San Diego.

“I feel that we’ll see a combination of technology (long distance in real time) collaborations in smaller spaces,” he said in an email. "The smart cities will start to rethink the outdoors.“

Britt’s ambient music is well-suited for an age of anxiety, but he also recorded a quarantine album of hip-hop beats as Soul Litchfield that will be a good fit when good times get rolling again. “I was so antsy! I needed to release the aggression.”

"The virus changes everything,” says Adam Weiner of Low Cut Connie, who has been performing Tough Cookies livestreams from South Philly since March. This month, he played a socially distanced live set at SteelStacks in Bethlehem that was also streamed to subscribers on the Patreon platform.

In the age of COVID-19 — both during and after the pandemic — fans will want their music in ways they already get their sports, says Weiner, who’s performing Monday as part of the Mann Center’s Virtual Party in the Park.

A Phillies fan “can watch them live, they can listen to them live, they can listen in Spanish. They can go to every game, they can go once a year, they can watch them on TV. They have all these entry points.”

The pandemic is teaching us, Bachynski says, “the profound value of music and sports and the arts ... to what we mean to each other. These are all really important parts of our humanity.”

Sports like men’s and women’s pro basketball have returned without fans, but have shown, Bachynski says, “that if you have public health measures in place and resources to do fast turnaround testing and protocols, it’s possible to create a bubble that’s safe.”

Achieving that with crowds would require discipline. “Unfortunately, human behavior is much more unpredictable than the virus.”

So the carefree pursuit of pleasure in our public lives won’t be roaring all the way back right away.

“Whenever we open things a little too soon or haven’t done it with sufficient precautions, the virus will be able to tell,” Bachynski says. “So I think it will be more a cyclical thing. We won’t be roaring. It’s far more likely that we’ll be stumbling back.”