WASTEWATER TESTING

 HOW DOES WASTEWATER TESTING WORK?

Watch the presentation where Gib Parrish and Dan Ostrye outline the past and current wastewater testing program for Yarmouth and how Covid trends can be spotted (6/9/22).

Yarmouth began a new U.S. CDC funded wastewater testing program on February 10, 2022. On April 13th, once we had the results of 12 wastewater samples under the new program, we restarted publishing our wastewater testing reports. Read it in the latest NEWS STORIES ABOUT WASTEWATER TESTING.

Pre-CDC: Every week until February 2022 we measured the total number of viral copies of SARS-CoV-2 in the Yarmouth wastewater over a 24 hour sampling period. This gives us an average number of viral copies per person. Because not everyone is infected with Covid, this means that those who are infected are shedding tens of billions of viral particles each day into the wastewater system.

WHAT DOES THIS TELL US?

We know that the Covid test results we are seeing from the Maine CDC are not telling us the full picture. By looking at a variety of sources of data we can get a clearer picture of how much Covid was circulating in Yarmouth during the prior week.

We take:

  • data from our wastewater testing in Yarmouth

  • data from the CDC on positive case numbers

  • data from the Yarmouth school system – both pooled testing, and positive cases reported

  • data from the Yarmouth Covid Task Force testing that happens every Monday.

This gives us a much fuller picture. Each week we produced a report summarising the results.

Here's a couple of charts that summarise the results we saw over the two years we ran the testing program.

 

Summary chart

Detailed chart

What next?

The Task Force program is transitioning to a wastewater testing program funded by the US CDC, which will test Yarmouth wastewater samples twice a week for the next year. More information about this new program can be found at https://www.cdc.gov/healthywater/surveillance/wastewater-surveillance/wastewater-surveillance.html.

The twice-weekly wastewater testing data for Cumberland County/Yarmouth and the six other participating towns in Maine can be found at https://covid.cdc.gov/covid-data-tracker/#wastewater-surveillance.

We are waiting to see how much local data we will actually be able to view once this is in place. Members of the Wastewater Testing Team of the Yarmouth Community Coronavirus Task Force will be regularly checking the data for Yarmouth produced by the new US CDC testing program.

We hope to be able to provide periodic reports to the Yarmouth Community about the trends in wastewater virus levels in the future, if the data is made available.

Thanks

The Team would like to thank the Town of Yarmouth, the Yarmouth Community Coronavirus Task Force, and individual donations for funding Yarmouth’s wastewater testing program from late-August 2021 through late-February 2022.

Thanks also to Chris Cline and Yarmouth Wastewater Treatment Facility staff for collecting the weekly samples; to Tom Downing, Gro Flatebo, Laura Coroi, Dan Ostrye, and Gib Parrish for transporting wastewater samples from the Treatment Facility to the laboratory at Saint Joseph’s College.

We would like to give a big "thank you" to Dr. Yolanda Brooks from St. Joes who worked with us for so long. She was an excellent partner and is taking the lead to write some of this up. She said it was "the opportunity of a lifetime". She will continue to provide support.

Gib Parrish and Sharon McDonnell