The U.S. Centers for Disease Control (CDC) published new travel restrictions for anyone trying to enter the United States, saying that travelers will have to submit a negative COVID-19 test one day before arriving. “As the virus that causes COVID-19 spreads, it has new opportunities to change (mutate) and become more difficult to control,” the CDC wrote in the new order, published this week (pdf). “While it is known and expected that viruses change through mutation leading to the emergence of new variants, the emergent Omicron variant is particularly concerning and of critical significance for this Amended Order.” The agency rationalized the move by saying that it’s not known whether the COVID-19 Omicron variant can breach the protection provided by vaccines. Tests that are approved by the U.S. Food and Drug Administration (FDA) are the only ones acceptable for use, the agency said. All passengers, including people who are fully …