COVID Wastewater Levels On The Rise In Boston Area

BOSTON — Earlier this month, city officials lifted Boston's mask mandate. Now, three weeks later, COVID-19 levels detected in the wastewater are on the rise.

Sewage data from the Massachusetts Water Resources Authority's study on COVID wastewater is often the first to predict a spike or surge in case numbers in the community, and after falling from steep levels during the omicron surge, those numbers are increasing.

According to the CDC, omicron BA.2, more commonly known as the "stealth" omicron variant, accounts for 72.6% of COVID cases circulating across the state, while comparing with about half of new infections nationally.

The new strain has several key mutations, with the most important of those occurring in the spike protein that studs the outside of the virus. Similar to the original omicron strain, BA.2 has genetic changes not seen in the initial version, the CDC says.

Right now, it has not been declared a variant of concern on its own.

While the amount of viral RNA in Deer Island Treatment Plant sewage doesn't come close to the peak levels we experienced in January, the newer rising levels bring up a topic of conversation for what should be done to combat what infectious disease experts believe could lead to inevitable spikes and surges in the future.

The samples are split between the authority's "North System" and "South System," which each contain part of Boston and surrounding communities. A map of the North and South systems is available here.

South of Boston's COVID wastewater average has increased 60% from the start of the month's low levels and the north of Boston's average has gone up 20%.

The plant serves 43 communities in greater Boston. Samples of wastewater are taken three to seven times a week and analyzed by Cambridge-based Biobot Analytics, according to the Massachusetts Water Resources Authority.

The recent increase in the COVID wastewater is likely due to the loosening up of mask mandates and businesses bringing people back in, said Davidson Hamer, a Boston University specialist in infectious diseases told the Boston Herald last week.

Infectious disease experts are also under the impression that the BA.2 variant is leading to spikes in European cases, along with lifted mask mandates indoors.

Back home, virus cases in schools continue to creep back up since the statewide universal school mask mandate was lifted four weeks ago.

According to state Department of Public Health data, more than 2,500 students and staff across the state tested positive for COVID-19 last week — up 30 percent from over a week ago.

As of Friday, the statewide seven-day rolling positive test average was back up to 2.08 percent following a low of 1.51 percent two weeks ago with cases rising in 143 communities.

Related

• Navigating COVID-19 On The North Shore 2 Years Later
• MA Town-By-Town COVID-19: Infection Rates Rise In 143 Communities