“By the time we have enough information to institute a travel ban, the cat’s already out of the bag, so to speak,” Nicole A. Errett, a professor at the University of Washington who has done research on public health emergency preparedness, said in an email. “Omicron has already been detected in other continents. A travel ban could in theory buy some time by reducing the spread of new seed cases, but we are talking on the order of days to weeks,” she added.
