The U.S. Centers for Disease Control and Prevention raised its COVID-19 travel advisory for Canada by one step to Level 4, the highest possible, and advised against travel to the country. 

The new guidance and the threat of the omicron variant underscore the notion that normal travel will likely not resume for some time, even between close politically and economically allied countries. 

The CDC also recommends against travel to France, Spain and Sweden. The omicron outbreak led the agency last month to discourage Americans from getting on cruise ships, regardless of the vaccination status.