COVID cases and hospitalizations are on the rise yet again, just as the school year kicks off, as a new variant with “lots of mutations” may lead to more infections in people who previously had COVID or who received vaccines and boosters.

The Massachusetts Department of Public Health on Thursday reported a weekly count of 2,171 virus cases, up 6% from last week’s count of 2,048 COVID cases.

The daily average of virus cases is now up to 310, more than four times the daily rate of 75 cases from the beginning of July.

There are now 342 patients hospitalized with COVID, up 42 patients from last week’s count of 300 patients. Hospitalizations had dipped to 100 patients in July.

In addition to the recent rise in local cases and hospitalizations, the Boston-area COVID wastewater has been ticking up — the first sign of more virus cases at the community level. The south-of-Boston wastewater average has gone up 36% in the last week, while the north-of-Boston average has jumped 55%.

This increase in cases and hospitalizations comes as a new variant BA.2.86 has been detected. The large number of mutations in BA.2.86 raises concerns that the variant will better evade existing immunity from vaccines and previous infections.

“Cases and hospitalizations are on the uptick and as such, people should use this as a time to check they are up to date on their boosters, especially those who are older or high risk,” said Matthew Fox, a Boston University School of Public Health epidemiology professor. “But even at the elevated rates we are seeing now, it is still not anything like what we’ve seen in the past. We are in a much better position with so much natural and vaccine induced immunity.

“There is a new variant of concern with lots of mutations, but we don’t yet know that that means anything in terms of infectiousness or severity, and often variants of concern never turn into anything serious,” he added. “So the key is for everyone to just make sure they are up to date on vaccinations.”

According to the CDC, scientists are evaluating the effectiveness of the forthcoming, updated COVID-19 vaccine. CDC’s current assessment is that this updated vaccine will be effective at reducing severe disease and hospitalization. At this point, there’s no evidence that this new variant is causing more severe illness.