‘It’s beginning to look like maybe it was just a bump’: COVID ticks down in Boston’s wastewater

"The best news of all is that there's very, very few deaths occurring."

This electron microscope image shows SARS-CoV-2 virus particles which cause COVID-19, isolated from a patient in the U.S., emerging from the surface of cells cultured in a lab. NIAID-RML via AP

After weeks of fearing that Boston could see a surge in COVID-19 cases and hospitalizations due to the introduction of the omicron BA.2 variant and an uptick both in cases and in COVID RNA found in the city’s wastewater, there is some indication that the city might have escaped a surge for now.

Though COVID RNA in the city’s wastewater, which has been recognized as a reliable predictor of community surges, began climbing again at the end of March, levels seem to be declining again, the Boston COVID wastewater data tracker shows.

COVID RNA in wastewater seems to have peaked in the Boston area around April 19, reaching nearly 700 copies per milliliter, but has since gone back down to a little over 500 copies per milliliter.


“We saw that little bump that occurred at the beginning of April. The question was: ‘Is that a bump or the beginning of something bigger?'” said Philip Landrigan, a pediatrician and the director of Boston College’s public health program.

“You never can say these things with 100% certainty, but I can say it’s beginning to look like maybe it was just a bump.”

Landrigan said another reason to be hopeful is because Massachusetts Department of Health COVID-19 data shows that case numbers across the state are starting to decrease.

Hospitalizations are still going up, Landrigan said, but they always lag behind wastewater data and case numbers.

“The best news of all is that there’s very, very few deaths occurring. Even though people are getting infected, I attribute the absence of deaths to the fact that the vaccine is just extraordinarily effective at keeping people alive,” he said.

But Johnathan Levy, the chair of the environmental health department at Boston University, wasn’t so optimistic.

First, he said, the wastewater in the northern part of the city’s tracking area has come down more than the southern part has, and the levels are still comparable to that of the end of February.


Also, he noted, some places in Massachusetts have increasing case numbers, while others have plateauing case numbers or decreasing case numbers, so the data is a mixed bag.

Finally, Walgreens COVID testing data still shows a sharp increase in the test positivity rate in the state of Massachusetts, and Boston’s test positivity rate has shown a modest increase.

“The wastewater data are a valuable indicator, [but] they’re not a fortune teller. And so it’s not telling us definitively where things are going to go,” he said.

Levy said it is especially important that we keep an eye on COVID data as families come back from traveling during school vacation week.

Still, he said, it’s good that right now most datasets are not showing a sharp increase.

“We’re hopefully starting to level or turn the corner, but I think we’re not certain,” Levy said.

Both Levy and Landrigan agreed that the recent bump was due to the introduction of the BA.2 variant into the community.

Still, the question remains: why didn’t Boston see the same rapid increase in cases and hospitalizations the U.K. did when BA.2 was introduced there?


Landrigan cites the the fact that 98% of people in Massachusetts have had at least one dose of the vaccine, and that nearly 79% in Massachusetts are fully vaccinated, as the reason for the lessened impact of the variant.


However, Levy pointed out, overall, the U.K. has a higher vaccination and booster rate than the U.S., with 90% of people having had at least one dose, 80% having been fully vaccinated, and 70% having had a booster.

Levy said the BA.2 variant having hit Massachusetts when the weather is beginning to warm may have helped lessen the spread of the variant, as more windows were being kept open and people spent more time outside.

Now, Levy said, we need to watch out for the BA.2.12.1 omicron variant, which is more transmissible than BA.2 and is spreading across the U.S.

He said there are also other variants popping up around the world that could cause more problems.

“We have to make sure that we’re doing the appropriate surveillance and that we’re hopefully taking measures to try to reduce the likelihood that we get a much worse variant coming down the line,” he said.


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