Data tracking the levels of coronavirus infections in the Boston area, through examination of sewer flow, has taken a dramatic plunge, reaching levels not seen since last summer.

The latest update on the Boston-area coronavirus wastewater tracker shows that both the south and north of Boston wastewater levels have sunk all the way back to low summer 2021 levels.

“This is great news indeed,” said Boston University epidemiology Professor Matthew Fox. “The wastewater data has been a very reliable predictor of things over the past few years, so I think we can be confident that rates of transmission will be low for some time.