Mayor Martin Walsh and his administration announced on November 17 that they would be releasing more COVID-19 metrics to the public moving forward, as well as adjusting the metric on positivity rate.
Walsh said that in Boston as of Monday, there were 239 new cases reported and four deaths since Friday.
“We’re going to continue to monitor the data that we have,” said Chief of Health and Human Services Marty Martinez, but data will now be released to the public twice a week using six metrics.
The metrics include new positive tests for COVID-19 in Boston residents, which Martinez told reporters on Tuesday “tells us how many new cases we’re seeing each day and how quickly COVID-19 is spreading in Boston.” Each of these metrics comes with a threshold of concern as well, and in this case it would be 339.6 cases per day or 50 cases per 100,000 residents per fay.
Another metric is positivity for COVID-19 in Boston residents, which shows the percentage of tests that are returning positive out of all those who are tested in a specific period of time. Martinez explained that a high positivity could indicate widespread infection in a particular community and/or “only a subset of the community at greatest risk for COVID infection is being tested.” In this case, the threshold of concern would be a positivity rate of 5 percent or higher or four or more Boston neighborhood rates above eight percent.
“Up to now, Boston has used a person-level approach using a cumulative time frame that looks back to the beginning of the epidemic,” the presentation said, “meaning each person is only counted once, even if they have been tested repeatedly.”
Moving forward, a hybrid model will be used that includes person-level and test-level positivity, and will not include college testing, though that will continue to be monitored separately, he said. He said the reason for this is to get a better look at positivity at the neighborhood level without college data skewing it.
“We think it more accurately depicts recent positivity due to a tighter time frame for testing,” and “provides a more accurate depiction of unique new positives,” Martinez said.
He said for those people who get tested multiple times a week, only one negative test will be counted, but any positive results get counted once every 90 days to prevent repeated reporting of the same positive test.
Martinez said that the current positivity rate in Boston as of November 12 using this metric is 5.4%, and the only one of the six metrics that has gone into the threshold of concern.
The third metric has to do with the number of COVID-19 molecular tests performed, which“helps us to understand whether we are performing a consistent amount of testing among Boston residents,” the presentation said. The threshold of concern here is a decrease in testing for three or more consecutive weeks, he said.
The final three metrics have to do with hospitals, and include “emergency department visits to Boston hospitals, the availability of adult ICU and adult medical or surgical beds at Boston hospitals, [and] percentage of non-surge adult ICU beds occupied at Boston hospitals,” according to a slide presented.
These metrics help the city understand hospital capacity so they can come up with a plan to increase capacity if need be,
So far, Martinez said that although there has been increased positivity, it has not turned into a high number of hospitalizations so far.
There is also a focus on equitable impact, Martinez said, including taking a hard look at data to find where inequities lie and “ensure that understanding was incorporated into these metrics,” as well as making sure more data by race, ethnicity, and age is available “given the disproportionate impact over the duration of COVID, and use these metrics to ensure equity across testing, isolation, and prevention messaging in the communities hit hardest by the virus.
Dr. Jennifer Lo of the Boston Public Health Commission (BPHC) said it is difficult for many people to pinpoint where exactly they contracted the virus, but household contacts have been a major cause for more cases, as one family member or roommate brigs it hoe to the rest of the household.
She also said that there have been a number of cases from workplace spread where people might have relaxed COVID distancing rules in the break room where masks are off for eating. She also said that vehicle sharing has been another cause of spread.
She said the BPHC is “monitoring those patterns,” and added that one person who may be particularly social could be just as quick of a spreader of the virus as super spreader events if they visit with multiple groups of people.
We are seeing it across the board,” Martinez said, between small gatherings, essential workers, people who travel—“it’s not just a couple scenarios,” he said.
“It’s important to us that our residents understand that the public health team is really focused on understanding what we’re seeing,” he said, and what that means and how the city can intervene to stop the numbers from getting out of control.
“If numbers continue to accelerate, we’re going to have to do more,” Walsh said at a press conference on Tuesday morning. “We’re going to put health and the health of our community first…there is no economic recovery without public health.”
He also announced that this week, 150 of the city’s highest-needs students were able to return to in person learning, but all other Boston Public School students continue to learn remotely.
For more information on COVID-19 and to view the data, visit boston.gov/coronavirus and bphc.org.