The task force added that its recommendation for was concerts in the United States and “countries deemed level 3 by the C.D.C.,” which includes much of Europe, but not Britain. But exactly how these changes would take effect remained unclear, including questions about refunds and rescheduled dates.

News of Live Nation’s decision to postpone tours was first reported by Billboard.

As the virus spreads, concert promoters, club operators and artists’ managers are contemplating a difficult year that could be full of postponements and cancellations — and with that, the potential for millions or even billions of dollars in lost income. The reach of Live Nation extends to many midsize clubs, like the House of Blues, which it also owns. And its choices may have a ripple effect on even independent venues across the country.

“It’s kind of an hour-by-hour scenario,” said Michael Dorf, a promoter and the founder of City Winery, an upscale club with locations in seven cities, including New York and Atlanta. Morgan Margolis, the chief executive of Knitting Factory Entertainment, which hosts shows at 11 venues across the country, said in a statement on Thursday that it was “monitoring the situation market by market, venue by venue, and tour by tour.”

Even before the Live Nation cancellation, the damage of the pandemic was severe in the music world, said Allen Kovac, manager of Mötley Crüe, which was set to begin a stadium tour in June. “You have people delaying on-sales for tours, and you have people who are going to postpone tours. It’s chaotic and stressful, from agents and managers to artists, their families and their support teams.”