WOBURN - Public health authorities say Woburn's COVID-19 outbreak wandered into troubled waters over the past week with the city's active caseload climbing to 28 people.
In its weekly coronavirus report issued on Wednesday afternoon, the Mass. Department of Public Health (DPH) classified Woburn as a "yellow" or warning community for the first time since state officials last month announced new metrics by which to judge the severity of community level outbreaks.
Based upon the data, Woburn's community incidence rate per 100,000 people has now climbed to 4.8. Last week, the city's incidence rate — based upon total confirmed COVID-19 cases over a two-week reporting window — stood at 3.4.
On Aug. 11, Mass. Governor Charles Baker and DPH managers described the case incidence rate metric as the most important factor for city and town officials to consider when making decisions about school reopening plans.
Highlighting the importance of the calculation, DPH each week releases a color-coded map that shades each community based upon their ranking as a white, green, yellow, or red level.
Early this morning, The Daily Times reached out to Superintendent Dr. Matthew Crowley's office to see if yesterday's report would have any impact on Woburn's decision to resume in-person classes on a part-time basis beginning on Sept. 21.
However, as of presstime, reporters had not yet heard back from the superintendent's office.
According to DPH's color-coded system, a white shade is assigned to any municipality that has five or fewer active COVID-19 cases, while a green label is given to cities and towns with an incidence rate of four or under.
Yellow classifications are for cities and towns with incident rates between 4 and 7.9, while the worst ranking, a red designation, is assigned to any community with a rate of eight or higher.
Technically, based upon guidance released by the Mass. Department of Elementary and Secondary Education (DESE), the School Committee's proposal to resume classes next week under a hybrid format should not be impacted by yesterday's report.
Specifically, in a memo to school superintendents across the state last month, DESE Commissioner Jeffrey C. Rlley argued that only districts with the worst "red" classification should be shifting away from classroom learning to a full-remote or at-home program.
In an explanation of the recommendation, Riley insisted communities with a yellow or better ranking should stick with hybrid or full in-person learning program.
Later stipulating any such decision should come after consultation with a local Board of Health, the state education department head did allow school officials some leeway to transition to a full-remote format after a yellow classification is reached.
"We expect these updated metrics and related guidance will support your decision-making both for school reopening and throughout the year if we encounter challenging circumstances," Riley wrote last month.
By the numbers
After releasing reoccurring COVID-19 reports based upon an entirely different format between March and early August, state authorities on Aug. 12 revamped the weekly analysis by adding the incidence rate and several other measurements. Until yesterday, Woburn had been ranked as a green community for five consecutive weeks.
According to the city's Board of Health, which maintains local COVID-19 records, a total of 730 individuals have tested positive for the virus since the pandemic began.
DPH officials say a total of 31 Woburnites were confirmed as having either traces of the virus or an antibody response to a COVID-19 infection over the past two weeks, when 2,189 residents of the city sought out testing. Only 28 of those residents are suspected of having active cases.
On Aug. 12, when the state released its first weekly community transmission under the revised format, Woburn's incidence rate was calculated to be a 2.9. At the time, about 19 individuals had tested positive for COVID-19, with 17 of those cases being considered "active".
The discrepancy between "active" — or individuals still considered contagious — and total positive results over the past 14 days is likely due to the availability of new testing methods, which now include antibody and antigen sampling kits.
The most common test, polymerase chain reaction (PCR) or molecular tests, are thought to confirm those who are presently infected with COVID-19 and thus most-likely to pass the virus onto others.
By contrast, antibody tests, which search for proteins the immune system creates to fight back infections, indicate an individual has recovered from the infection and are no longer at risk of spreading the contagion.
Unlike PCR tests that look for DNA sequences associated COVID-19, antigen tests search for protein strands that are associated with the pathogen. DPH officials say such tests results are more susceptible to false readings., so a positive antigen report is not sufficient to officially record a new COVID-19 case.
Though much attention is being paid to the new metrics due to their ties to school reopening plans and other potential community-level travel and gathering restrictions, Woburn like many area communities has witnessed a drastic reduction in the spread of the pathogen.
For example, while the latest DPH report shows 31 residents testing positive for COVID-19 during the previous 14 days, the local Board of Health tracked a larger increase in a single-day during the height of the pandemic last spring, when some 43 new cases were reported on May 10.
In perhaps a more fitting illustration, in stark contrast to the 31 recent cases reported over the past 14 days, between April 22 and May 6, Woburn's COVID-19 totals soared by 172 cases — the number of residents to test positive for the contagion climbed from 224 to 403 cases.