WASHINGTON, June 9 (Xinhua) -- The U.S. Centers for Disease Control and Prevention (CDC) has revised travel recommendations for dozens of countries to a lower risk tier, adjusting travel guidance for vaccinated Americans.

Travelers wearing face masks line up for security checks at O'Hare International Airport in Chicago, the United States, on Nov. 25, 2020. (Photo by Joel Lerner/Xinhua)

The CDC lowered over 60 countries from "COVID-19 very high" Level 4 tier to "COVID-19 high" Level 3 tier on its updated travel recommendations list, including Japan, Canada, Mexico, Italy, France and Germany.

The CDC calls for travelers to be fully vaccinated before traveling to destinations with COVID-19 infections.

The changes came as vaccination rates across the United States continue to increase. About 51.8 percent of the U.S. population had at least one dose of a COVID-19 vaccine and 42.5 percent were fully vaccinated as of Wednesday, according to CDC data.