Guidelines issued by the agency in June recommended various ways to minimize crowds at polling locations, including absentee voting and extended voting hours.

To cut down on disease transmission, the C.D.C. also recommended putting up physical barriers between voting machines; spacing the machines apart from one another; indicating 6-foot distances with signs or floor markings for those waiting in line to vote; designating separate entrances and exits; the use of protective gear — masks, face shields, gloves and gowns — for poll workers assisting sick voters; and allowing curbside voting for people who are ill.

“Ensuring that ill voters can vote while maintaining poll worker and voter safety will be essential to minimizing transmission without restricting voting rights,” the report said.