U.S. Department of Health & Human Services

11/21/2020 | Press release | Distributed by Public on 11/21/2020 18:16

How CDC Determines the Level of a Country’s COVID-19 Travel Health Notice

CDC uses Travel Health Notices (THNs) to alert travelers and other audiences to health threats around the world and how to protect themselves. On November 21, 2020, CDC adapted its 3-level notice system to a new 4-level system for COVID-19 and updated criteria used to determine THN levels.

COVID-19 Travel Health Notice information can be found in two places:

This new 4-level system categorizes destinations, including international destinations and United States Territories, into the following four levels:

  • Level 4: Very high level of COVID-19
  • Level 3: High level of COVID-19
  • Level 2: Moderate level of COVID-19
  • Level 1: Low level of COVID-19

CDC uses primary and secondary criteria to determine COVID-19 Travel Health Notice levels

Primary Criteria

CDC reviews data reported to the World Health Organizationexternal icon to determine a destination's COVID-19 Travel Health Notice level.

Primary criteria for destinations with populations over 200,000

  1. Incidence rate (cumulative new cases per 100,000 people over the past 28 days)
  2. New case trajectory (Are new cases over the past 28 days increasing, decreasing, or stable?)
LEVEL 4

VERY HIGH Level

LEVEL 3

HIGH Level

LEVEL 2

MODERATE Level

LEVEL 1

LOW Level

Incidence Rate

(cases per 100,000 people over past 28 days)

More than 100 51-100 5-50 Less than 5

Primary criteria for destinations with a population of 200,000 or less

  1. COVID-19 case counts (cumulative new cases over the past 28 days)
  2. New case trajectory (Are new cases over the past 28 days increasing, decreasing, or stable?)
LEVEL 4

VERY HIGH Level

LEVEL 3

HIGH Level

LEVEL 2

MODERATE Level

LEVEL 1

LOW Level

Case Count

(over past 28 days)

More than 100 51-100 10-50 Less than 10

Secondary Criteria

CDC uses hospitalization rates and cumulative testing positivity rate as secondary criteria to validate the primary criteria. Both primary and secondary criteria are measured over 28 days. Secondary criteria data are obtained from official sources, such as ministry of health websites. CDC reviews secondary criteria for all destinations, regardless of population size.

Lowering a Travel Health Notice Level