Cyrus has called off a trip to Australia, where she was due to headline a bushfire benefit concert.
Two Madonna shows in Paris have been cancelled after French authorities banned large gatherings.
And Pearl Jam have postponed their US and Canada tour, saying the risk "is simply too high for our comfort level".
Meanwhile, reports say the Coachella music festival in California will be put back to October. The most high-profile festival in the US, it was due to take place in April and be headlined by Rage Against the Machine, Travis Scott and Frank Ocean.