In a statement on its website, CDC said that “if a destination does not provide data, their THN level is designated as ‘unknown’ and travelers are advised to follow THN Level 4 recommendations,” which is to avoid travel there entirely. “Because the current situation in Singapore is unknown, even fully vaccinated travelers may be at risk for getting and spreading Covid-19 variants,” the CDC said.
The U.S. agency has reversed errant designations before. In September, the CDC mistakenly flagged Hong Kong as a growing risk for Covid, despite minimal cases there at the time. It later revised the designation down to its lowest risk level.