COVID Is Rising in Mass. Wastewater. Here's What Experts Say That Means

Massachusetts COVID-19 wastewater data has shown rising levels of the virus in recent weeks, which Tufts Medical Center's Dr. Shira Doron said called "pretty dramatic"

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After weeks of hitting a plateau, COVID-19 levels could be making a comeback in Massachusetts.

Data shows that the amount of COVID-19 being detected in Massachusetts wastewater is on the rise, which three Boston doctors said could be a sign of a forthcoming surge in cases during NBC10 Boston's latest "COVID Q&A" discussion. But it's becoming more and more difficult to measure exactly how much coronavirus is circulating in the community.

"I think the increase in wastewater levels is certainly concerning," Brigham and Women's Chief of Infectious Disease Dr. Daniel Kuritzkes said. "It could very well be a harbinger of a surge to come."

The latest data from the Massachusetts Water Resources Authority shows the amount of virus copies per milliliter of wastewater is trending upward in communities on both the north and south systems.

"The wastewater increase is pretty dramatic, you know? Really a steep jump," Tufts Medical Center's Dr. Shira Doron said.

The wastewater numbers, which have become an important tool in tracking COVID activity in the Bay State throughout the pandemic, come from the MWRA's pilot study that analyzes wastewater processed at the Deer Island Treatment Plant. It may now be the best indicator of community risk levels, according to Boston Medical Center's Dr. Davidson Hamer, who emphasized that the available data has "really significant" limitations.

The seven-day COVID wastewater average north of Boston is up more than 100%, according to the Boston Herald.

"We can't just look at the case count anymore," Hamer said, noting that Massachusetts moved from reporting daily to weekly case counts over the summer. Universities are no longer doing asymptomatic surveillance like they were through the spring, Hamer added.

The Massachusetts Department of Public Health's COVID-19 dashboard shows that cases and hospitalizations have hit a plateau since coming down from the omicron surge in February, then another peak in May. But it likely isn't showing the complete picture because so many people use at-home testing kits, the doctors said.

"That increase in cases may not even be detectable using our regular dashboard because an enormous proportion of actual infections don't get reported to the state if the testing was done at home or because people don't test," Doron said. "This was the reason why it took so long to get home tests, because public health officials were afraid that we would lose our ability to know what the state of the pandemic was. And I think that the availability of home tests is more important than the ability to know where we are in the pandemic. It has been a game changer and it has been great for public health. But we are really flying blind now in terms of knowing what's happening."

The wastewater measurements aren't perfect either, though. The data can be manipulated by outside variables, including inclement weather, Doron noted. But if the increase is accurate, then the data does suggest that Massachusetts will see a spike in cases, though perhaps not through the state's dashboard.

We are really flying blind now in terms of knowing what's happening.

Dr. Shira Doron, hospital epidemiologist at Tufts Medical Center

"So how will we know that's even happening? It will manifest in absenteeism from work in all of the sectors. It could manifest in increased hospitalizations," Doron said. "It's just really difficult to know where we are at any given moment in time in this pandemic. And we always need to stay ready to scale up our efforts -- to scale up testing, to scale up treatment, to scale up vaccination, to scale up hospital capacity."

Hospitalizations are another important indicator to keep an eye on, according to Kuritzkes. Hospitalization rates will always rise when cases are up, the doctors said, because they include patients who are in the hospital with COVID-19 and those who are not in the hospital for COVID-19. Massachusetts is the only state that separates those out.

"Whether this will truly be a surge or not, and what the consequences of that surge might be, are very hard to tell," Kuritzkes said. "It's important for everybody to remember that there's still ways that people can protect themselves, particularly getting boosted, which will at least protect against severe disease."

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