The protests called to mind the Liberty Loan parades in 1918, which served as potent vectors for the killer flu. And yet, in 2020, the marches did not appear to be significant drivers of transmission. “We tested thousands of people,” Michael Osterholm, the director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told me. “We saw no appreciable impact.” One study found lower rates of infection among marchers than in the surrounding community. Epidemiologists concluded that mask-wearing and being outdoors protected the marchers.
