The proposal comes as boosters have become a hard sell.
The CDC has been warning about breakthrough COVID-19 infections for the better part of 2021, issuing an update in April that said, "People can still get sick and possibly spread COVID-19 to others after being fully vaccinated." During the outbreak of the delta variant over the summer, the CDC updated its guidance for fully vaccinated people, saying they should wear masks in crowded indoor areas because of the high transmissibility of the variant. While the COVID-19 vaccines can prevent severe illness, hospitalizations and death, breakthrough infections still can and do occur, the CDC said.
Senator Elizabeth Warren, a Massachusetts Democrat, announced her positive COVID-19 test on Twitter Sunday afternoon. Warren is fully vaccinated, meaning she has contracted a breakthrough infection.