For months, Mr. Pence was seen in public flouting the guidance from public health officials to wear a mask when in proximity to others. He refused to put one on when he visited the Mayo Clinic at the height of the first wave of infections in April, even as other members of the administration traveling with him did.

A few weeks later he wrote an op-ed for The Wall Street Journal titled “There Isn’t a Coronavirus ‘Second Wave.’” Even after members of his own staff caught the virus, including his chief of staff, Mr. Pence continued to attend and host official social gatherings, including a holiday party at the vice president’s residence this week where guests mingled in an outdoor tent and posed for pictures without masks, according to attendees.

Like most other Republicans, Mr. Pence has never second-guessed Mr. Trump’s leadership during the pandemic. He insisted in August in an interview with “Good Morning America” that he “couldn’t be more proud of the leadership President Trump has provided from the early days of the coronavirus pandemic.”