How CDC Determines the Risk Level for COVID-19 Travel Health Notices

CDC uses Travel Health Notices (THNs) to tell travelers and other audiences about health threats around the world. On March 27, 2020, CDC posted a Level 3 Global COVID-19 Pandemic Notice. That notice advised travelers from the United States to avoid all nonessential travel to foreign countries and US Territories around the world. On August 6, 2020, CDC replaced the global travel notice with destination-specific COVID-19 THNs.

CDC also uses an interactive world map (COVID-19 Travel Recommendations by Destination) to share COVID-19 travel recommendations. On this map, foreign countries and US Territories are shown as Level 3 (high risk), Level 2 (moderate risk), Level 1 (low risk), or no THN (very low risk). The map also identifies destinations where we cannot make a risk determination (no data available).

Criteria Used to Determine COVID-19 Travel Health Notice Risk Levels

CDC bases COVID-19 risk levels for foreign countries and US Territories on two sets of data (primary and secondary criteria)

• Virus transmission rates at the destination (primary criteria)
  AND
• Healthcare capacity and public health infrastructure at the destination (secondary criteria)

Primary Criteria: Virus Transmission Rates

CDC uses World Health Organization COVID-19 surveillance dataexternal icon to measure virus transmission rates; we monitor this information every day. Population size determines the specific criteria CDC uses.

For foreign countries and US Territories with more than 300,000 people, CDC reviews three primary criteria

• New COVID-19 case counts
• Incidence rate (new cases per 100,000 people), and
• New case trajectory (whether the number of new cases is going up, going down, or staying the same over time)

For foreign countries and US Territories with 300,000 people or less, CDC reviews two primary criteria

• New COVID-19 case counts, and
• New case trajectory

*CDC reviews all primary criteria daily; see below for how a destination moves from one THN level to another.

Secondary Criteria: Healthcare Capacity and Public Health Infrastructure

CDC uses secondary criteria to measure the impact of COVID-19 on essential health services (healthcare and public health). Secondary criteria are mostly qualitative data that come from official sources, such as ministry of health websites. We review the same secondary criteria for destinations with more than 300,000 people as for those with 300,000 people or less.

Examples of secondary criteria

• Healthcare capacity, such as available hospital beds and ventilators
• Public health infrastructure, such as testing and contact tracing capacity
• Any documented exported cases (an exported COVID-19 case is defined as a traveler who leaves one foreign country or US Territory and enters another)

Changing COVID-19 Travel Health Notice Levels

De-escalating a Travel Health Notice Level

• CDC monitors primary criteria for all foreign countries and US Territories daily.
• A foreign country or US Territory is eligible to de-escalate from a higher THN level (more COVID-19 risk) to a lower THN level (less COVID-19 risk) when all primary criteria remain below Level 3 (or Level 2 or Level 1) thresholds for 28 consecutive days, 2 incubation periods for COVID-19. The incubation period is the time it takes for a person exposed to the virus to develop infection, usually 2 to 14 days for COVID-19.
• When a destination meets primary criteria thresholds for de-escalation for 28 consecutive days, CDC then reviews the secondary criteria. If secondary criteria show that both the healthcare and public health systems are meeting the needs of the population, CDC will de-escalate the THN.
• If secondary criteria for a foreign country or US Territory are unavailable or are inconsistent, the destination will stay at its current THN level, typically Level 3. CDC will continue to monitor secondary criteria as long as primary criteria remain below Level 3 thresholds.
• CDC’s risk assessment process is designed to protect US travelers. We de-escalate destinations to the highest level of risk indicated by the primary criteria. CDC will remove a THN for a destination (i.e., de-escalate to a very low COVID-19 risk) if all primary criteria fall below Level 1 thresholds and all secondary criteria are met.
• For all de-escalated foreign countries and US Territories (THN Level 2 or 1, or no THN), CDC monitors secondary criteria monthly to ensure ongoing consistency.

Escalating a Travel Health Notice Level

• A destination can be escalated to a higher level THN when its primary criteria demonstrate new case counts and/or incidence rates and/or a new case trajectory that exceed the thresholds of its current THN level (Level 2 or 1, or no THN).
• Foreign countries and US Territories with more than 300,000 people: CDC will escalate the THN level of any destination that fails to consistently meet primary criteria over 14 consecutive days (new case counts and/or incidence rates have increased and/or the new case trajectory has increased).
• Foreign countries and US Territories with 300,000 people or less: CDC will escalate the THN level of any destination that fails to consistently meet primary criteria over 14 consecutive days (new case counts and/or the new case trajectory have increased).
• Foreign countries and US Territories of any population: CDC can also escalate a destination’s THN level sooner than 14 days if primary criteria demonstrate sudden or abrupt increases in COVID-19 risk for 7-14 consecutive days.