Here's what Nantucket's wastewater is showing about the number of COVID cases on island

The good news about declining levels of COVID-19 in Boston’s wastewater is that it's a trend spreading to the Cape and Islands.

The latest wastewater test report from Nantucket shows a sharp decline in viral loads, said Jerico Mele, Nantucket director of human services.

"We are seeing the wastewater count drop off in a manner similar to Boston’s recently. We may start seeing a drop in cases next week," Mele said.

The new report posted online Thursday follows on the heels of a record spike in viral loads reported Jan. 12.

“The concentration number went through the roof" at that time, Mele said.

“The amount of virus in the wastewater basically broke every record we’ve had for viral concentration for the last three weeks running,” Mele said.

But this week the copies of viral RNA per liter of sewage, adjusted for flow, dropped to approximately 3.3 million, down from 4.8 million last week.

It looks like good news, especially if the trend continues, Mele said.

The Nantucket decline came a week or so after the Massachusetts Water Resources Authority's Deer Island Treatment Plant, in Boston Harbor, reported declining levels of COVID-19 in the wastewater.

Provincetown wastewater test result show increase

The results from wastewater testing Provincetown are a bit more mixed.

“The latest (wastewater test result) is up,” said Richard J. Waldo, director of Provincetown’s Department of Public Works.

“Is it spiking to the level of the outbreak we saw (last summer) with Provincetown? No,” Waldo said.

Provincetown made international news with a surge in COVID-19 cases last summer following the Fourth of July weekend.

The latest report from Jan. 5 shows a viral load that is approximately one-third lower than the summer's record peak, but it also represents an increase over more recent test results.

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Test results from Jan. 1 and Jan. 3 showed a dip in coronavirus loads, with 545,197 copies per liter and 451,487 copies per liter, respectively, Waldo said.

But the Jan. 5 report showed a jump to about 2.3 million copies of viral RNA per liter of sewage.

There are multiple factors that can explain the difference in viral loads, Waldo said, adding that the time of day the tests are run and whether the testing coincides with weekend visitors can influence test results.

“You have to observe it over time."

He said the overall trend in Provincetown had been increasing, but he was waiting to see what the latest test results show, especially since the wastewater plant didn't conduct testing last week due to a short staff.

The new test results will be out later this week or early next week, he said.

Waldo said he expected to see a decline in viral loads soon.

"I think we've hit our peak."

Mele said wastewater results show the direction infections will take about a week after the test report.

Barnstable County seven-day average for new cases shows decline

But in a press teleconference Thursday morning, state Sen. Julian Cyr, D-Truro, said COVID-19 cases already appear to be on the decline locally.

The seven-day average for new cases in Barnstable County is running about 272 a day, Cyr said.

“That’s less than the 400s we were seeing last week.”

Cyr said he believes Jan. 3 to 11 represented the peak of COVID-19 cases on Cape Cod.

Sean O'Brien, director of Barnstable County's department of health and environment, said it appeared the county was "climbing down the backside of a mountain" when it came to new COVID-19 cases.

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But during the teleconference he pleaded with the public to avoid large gatherings, wear a mask indoors and get vaccinated and boosted.

Cyr said that even though numbers of new cases appear to be on a downward trend, the testing positivity rate for many towns on the Cape remain at 15%, which is considered an outbreak level.

In the last two-week period reported by state public health officials Jan. 13, Nantucket had 460 new cases of COVID-19, which accounts for 16.7% of 2,753 COVID-19 cases on Nantucket since the start of the pandemic.

Provincetown, like the rest of the Cape and the state, also has seen a surge in cases, with 34 new COVID-19 infections in the same two-week time period — for a total of 403 cases since the pandemic began.

Both Provincetown and Nantucket are working with Cambridge-based Biobot Analytics to track viral loads in wastewater.

Biobot was selected by the U.S. Department of Health and Human Services to analyze wastewater samples from more than 300 treatment plants serving more than 100 million people across the U.S., according to The Associated Press.

Cases of omicron, which are responsible for the latest surge, already have peaked in Great Britain.

U.S. Surgeon General Dr. Vivek Murthy on Sunday said in some parts of the U.S., particularly the Northeast, cases have begun to plateau or even decline.

But Murthy said parts of the U.S. that saw omicron hit later will be dealing with it for a while. "The next few weeks will be tough."

Waldo said he doesn't know why coronavirus test results from Boston showed a decline in viral loads at the same time Provincetown's loads remained elevated.

Due to the amount of flow going through the Deer Island Treatment Plan, the samples may be a little more diluted than they are locally, Waldo said.

Or "there could be some kind of lag behind the big city."

This article originally appeared on Cape Cod Times: COVID-19 wastewater data shows decline on Nantucket