Editor’s note: As of July 1, the Massachusetts Department of Public Health stopped reporting COVID-19 risk designations for individual communities and as a result, we are no longer updating this page. It was last updated June 24.
Massachusetts’ weekly public health reports show how town-by-town risk for coronavirus spread has fluctuated over a period stretching from mid-October to mid-June.
The state releases risk data on a weekly basis, and each map represents data from a two-week period. These maps lay out the data since the Nov. 6 public health report, when the state began evaluating risk using a combination of percent positivity and daily incidence rate per 100,000 people. While these maps represent 33 weekly public health reports, they represent 32 weeks of data.
On Nov. 6, when the state changed its metrics for determining the risk level of COVID-19 transmission, 16 communities were considered high risk,
The number steadily rose from there, to 30, to 62, to 81, 97, 158, 187, 188, 190, 219, before peaking at 229 and then falling to 222, 192, 153, 110, 66, 28, 19, 14, 20, 32, 55, 77, 59, 48, 26, 13, 6, 2, 1, and 0. This week was also the third in which zero communities were deemed to be at moderate risk for COVID-19.
Boston, which at one point spent nearly a month in the high-risk category, is now considered lower risk. The city’s positivity rate slowly increased from 1.12 percent over the period of Oct. 18 to 31, to a peak of 5.94 percent percent over the period from Dec. 20 to Jan. 2 and its average rate of positive tests per 100,000 went from 18.4 for the report covering Oct. 18 to 31, to a peak of 72.4 for the report covering Dec. 27 to Jan. 9.
In the state’s most recent report, covering data from June 6 to June 19, Boston had a positivity rate of 0.31 percent and an average daily incidence rate of 1.4 cases per 100,000 people.
Explore the state’s recent risk maps here:
The map includes a color-coded ranking system, by town size. Here’s how to track the map:
For towns with under 10,000 people:
Grey (lowest risk): Less than or equal to 10 total cases.
Green (lower risk): Less than or equal to 15 total cases.
Yellow (moderate risk): Less than or equal to 25 total cases.
Red (high risk): More than 25 total cases.
For towns with 10,000-50,000 people
Grey: Less than or equal to 10 total cases.
Green: Less than 10 cases per 100,000 people and more than 10 total cases.
Yellow: 10 or more cases per 100,000 people, or a positivity rate equal or greater to 5 percent.
Red: 10 or more cases per 100,000 people, and a positivity rate equal or greater to 5 percent.
For towns with more than 50,000 people
Grey: Less than or equal to 15 total cases.
Green: Less than 10 cases per 100,000 people and more than 15 total cases.
Yellow: 10 or more cases per 100,000 people, or a positivity rate equal or greater to 4 percent.
Red: 10 or more cases per 100,000 people, and a positivity rate equal or greater to 4 percent.
Before it changed its metrics on Nov. 6, the state had evaluated risk solely on the basis of the daily incidence rate, with an exception for communities with fewer than 5 total cases.
Peter Bailey-Wells can be reached at email@example.com. Follow him on Twitter @pbaileywells. Amanda Kaufman can be reached at firstname.lastname@example.org. Follow her on Twitter @amandakauf1.