On January 6, 2021, supporters of President Donald Trump stormed the United States Capitol building to disrupt the certification of Joe Biden's electoral victory. At least one activist participated in the riot despite a recent positive COVID-19 diagnosis, and few members of the crowd wore face coverings, with many coming from out of town. A group of maskless Republicans sheltering in place were recorded refusing masks offered by Representative Lisa Blunt Rochester (D-DE), and as many as two hundred congressional staffers reportedly sheltered in various rooms inside the Capitol, further increasing the risk of transmission. Brian P. Monahan, the attending physician of Congress, later reported that members of Congress may have been exposed to others with COVID-19 while sheltering in place. Four members of Congress have since tested positive due to the exposure.