Editor’s note: The Greenfield Recorder plans to provide regular updates on the risk level of COVID-19 transmission as wastewater testing results are received.
With health officials seeing higher volumes of infection in wastewater results and an elevated percent positivity last week, the risk for COVID-19 remains high in the four communities involved in the Contact Tracing Collaborative.
Virus concentration in Greenfield’s wastewater increased from 392,863 copies of virus per liter of sewage (which accounts for dilution and other factors) to 2.4 million copies between Oct. 12 and Oct. 19, according to the latest data from Biobot Analytics. According to Health Director Jennifer Hoffman, all four communities involved in the collaborative have seen elevated rates of positivity, with Greenfield at 10.7%, Montague at 19%, Deerfield at 9.6% and Sunderland at 11.7%.
The four communities saw three hospitalizations over the past week, down from five in the previous week, and cluster events (infections of three or more people at one site) remained stable at six.
The Contact Tracing Collaborative created a traffic light alert system, outlining thresholds for low, moderate and high risk of COVID-19 transmission in an effort to illustrate case levels and provide residents with guidance for masking. Given these communities are now in the red zone with a high risk of COVID-19 transmission, masking is recommended.
In combination with wastewater testing — people with an active COVID-19 infection excrete the virus in their stool, and samples from wastewater treatment plants can be analyzed to estimate community virus levels — the four municipalities factor in hospitalization numbers, positivity rates and case numbers to determine risk levels. Health officials also continue to talk with nursing homes, businesses and schools to track cluster infections.
The following three zones, defined by the Contact Tracing Collaborative, are used to gauge risk levels of COVID-19 transmission in the four communities. For the risk level in the area to change, at least two measures need to apply.
Masking recommended.
■Cluster infections (of three or more people at one site): five or more.
■Percent positive tests out of total tests performed: greater than 10%.
■Hospitalizations: five or more.
■Increase in case trend.
■Increases in wastewater trend.
Masking encouraged.
■■One to four cluster infections.
■Stable positive testing.
■Fewer than five hospitalizations.
■Stable case incidence.
Masking optional.
■No cluster infections.
■Decrease in positive tests.
■Decrease in hospitalizations.
■Decrease in case incidence.
■Decreased virus copies in wastewater.