[504]
Trump often refused to wear a face mask at public events, contrary to his own administration's April 2020 guidance that Americans should wear masks in public[505] and despite nearly unanimous medical consensus that masks are important to preventing the spread of the virus.[506] By June, Trump had said masks were a "double-edged sword"; ridiculed Biden for wearing masks; continually emphasized that mask-wearing was optional; and suggested that wearing a mask was a political statement against him personally.[506] Trump's contradiction of medical recommendations weakened national efforts to mitigate the pandemic.[505][506]
Despite record numbers of COVID-19 cases in the U.S. from mid-June onward and an increasing percentage of positive test results, Trump largely continued to downplay the pandemic, including his false claim in early July 2020 that 99 percent of COVID-19 cases are "totally harmless".[507][508] He also began insisting that all states should open schools to in-person education in the fall despite a July spike in reported cases.[509]

Political pressure on health agencies
Main article: Trump administration political interference with science agencies
Trump repeatedly pressured federal health agencies to take actions he favored,[497] such as approving unproven treatments[510][511] or speeding up the approval of vaccines.