U.S. warns against travel to 80% of world due to coronavirus

The United States hasn't had a global advisory warning against international travel since August, when guidance was revoked by the Trump administration.

The advice issued by the department isn't a formal global advisory. Instead, it says the State Department will start using Centers for Disease Control and Prevention standards as it prepares health and safety guidelines for individual countries. Because of those standards, about 80% of countries will be classified as "Level 4" or "do not travel."

Travel is also discouraged for the remaining 20%, though not as emphatically. It says people with plans to visit those countries should reconsider before proceeding.