COVID-19 Area Risk (CAR) scoring system developed for quarantine and testing requirements

(CDC photo)

Unique to Guam and developed by Governor Lou Leon Guerrero’s Physicians Advisory Group, the COVID-19 Area Risk (CAR) Score is now the primary tool used to assess the risk of an area’s potential to spread COVID-19 to other states or countries through travel.

The CAR Score was first implemented on July 1, 2020 as part of Guam’s Quarantine Protocol for incoming travelers.

The current scoring system factors in three key assessments:

· Case Doubling Time

· Test Positivity Rate

· New Cases Per 100K Population

Case Doubling Time relates to the speed at which coronavirus has the potential to spread exponentially. It measures, as the name would suggest, how many days it takes for the number of coronavirus cases to double.

For example, during the first two weeks of Guam’s public health emergency, the Case Doubling Time was 3 days, which meant that our total number of cases on average doubled every 3 days during that two-week period. Currently, our Case Doubling Time over the past two weeks is calculated to be 189 days.

Test Positivity Rate refers to the percentage of people who have tested positive for COVID-19 out of the total number of those who have been tested.

New Cases Per 100K Population is a ratio used to track the rate of COVID-19 cases per capita in a jurisdiction.

CAR Score

To be considered a Low Risk Area, a country, state, or territory must have a CAR score of 5.0 or less. An example of an area that has a CAR score of 5.0 or less may have the following combination of metrics:

· Case Doubling Time >256 Days

· Test Positivity Rate <2%

· New Cases Per 100K Population <2

A jurisdiction can still achieve a favorable CAR score with any of the individual metric values if offset by other scoring factors. For example, 256 Case Doubling Time, 2.5% Test Positivity Rate, but with a lower score of 1.5 New Cases Per 100K Population will still equate to a CAR Score of 5.

Source Material

The CAR Score uses source data provided by the World Health Organization (W.H.O.), the U.S. Centers for Disease Control and Prevention (CDC), U.S. Department of Health and Human Services (HHS), New York Times, the COVID Tracking Project, and Our World in Data.

Data used to determine CAR Scores is reviewed regularly and scores will be reported approximately every 14 days.

(Office of the Governor)