Boston-area COVID wastewater spikes to January levels: ‘We are in the throes of a new wave’

It’s never a good sign when you see the phrase, “The highest COVID levels since January.”

That’s now the case with the Boston-area COVID wastewater tracker, as the closely monitored predictive data shows a spike back to high January levels that stemmed from the initial omicron surge. Now, the spring wave is being fueled by the omicron BA.2 variant, along with a subvariant identified as BA.2.12.1.

On the Boston COVID wastewater tracker, a recent daily sample from the south-of-Boston region was the highest single-day count since Jan. 22. Also, a daily sample from north of the city was that region’s highest count since Jan. 19.

“It definitely looks like we are in the throes of a new wave given the wastewater data and the recent increased number of positive cases in Massachusetts,” said Davidson Hamer, a Boston University School of Public Health infectious diseases specialist. “It looks like this is being driven primarily by BA.2.12.1, a specific subvariant of BA.2.

“I fear that this is going to continue to surge for several weeks especially given graduations, commencement, parties, celebrations of the Celtics playoff victories, and removal or loosening of mask mandates,” he added.

The south-of-Boston COVID wastewater average has spiked 92% since the start of May, and the north-of-Boston average has jumped 84%.

The averages for both regions are similar to late January levels, but are significantly lower than the omicron peak; the south average peak was 11,446 copies per milliliter compared to the current 1,113 copies, and the north peak was 8,644 copies compared to the current 1,035 copies.

“I suspect that the total peak will not be as high in terms of the number of cases or wastewater data as the omicron wave in January,” Hamer said. “Hopefully the new wave will subside by mid- to late-June but this is just my best guess.”

The sewage data is the earliest sign of future virus cases in the community. Reported COVID infections have been rising in recent weeks across the state.

“The wastewater data is going up faster than we’d like to see and you are starting to see action being taken like increased masking in schools and workplaces,” said Matthew Fox, a Boston University School of Public Health epidemiology professor, who noted that this rise is somewhat surprising given the prior omicron wave.

“At the same time, the data are not super high at the moment and so we don’t know whether this is indicative of a big wave or a small one,” he added. “I still think that immunity from the past wave means this one will not be as bad as the last, but there is no way to know for sure and we will have to see if that is the case. I think the real message is we should be starting to take more precautions and anyone who is not vaccinated should get vaccinated as soon as possible.”