On April 13, 2022 the CDC announced significant changes to the Travel Health Notices (THN) specific to COVID-19. The structure of the 4 level system will reserve the highest level-'Level 4: Do Not Travel' for only special circumstances such as a healthcare infrastructure collapse or extreme spikes in case counts of COVID-19 levels. This change resulted in 89 countries being removed from the "Level 4: Do Not Travel" list.
CDC Travel Health Notices for Levels 1, 2, and 3 will continue to be based on a 28-day incidence or case counts.
The 4 COVID-19 Travel Health Notice levels are:
Level 4 – Special Circumstances/Do Not Travel
Level 3 – High Level of COVID-19
Level 2 – Moderate Level of COVID-19
Level 1 - Low Level of COVID-19
Level Unknown: Unknown Level of COVID-19
Read more from the CDC on how COVID-19 Travel Health Notices are determined here.