An aide for Collins noted that she was never planning to attend the GOP convention because she does not go when she herself is up for reelection. Collins is in a tight race this year that could be pivotal in determining who holds the Senate majority in the next Congress.

Spokespeople for Romney and Murkowski didn’t immediately respond to follow up questions about whether their plans were related to the coronavirus, as the country sees an increase in cases.

Both senators have had high-profile clashes with Trump; Romney was the only Republican senator to vote to impeach the president earlier this year, while Murkowski opposed ObamaCare repeal and Supreme Justice Brett Kavanaugh’s nomination.