GREENFIELD — Cases of COVID-19 have been on the rise throughout the Pioneer Valley over the past month, although not to the extent that they were a year ago, according to health officials.

In Greenfield, the transmission risk level remains “high” for the second week in a row, according to the Contact Tracing Collaborative, which consists of Greenfield, Deerfield, Montague and Sunderland. Friday’s weekly update on transmission risk comes as cluster infections (of three or more people at one site) remain high at six, and the positivity rate reaches 10.6% compared to 9% last week. Average daily hospitalizations, meanwhile, dropped from 2.25 last week to 1.6 this week.

Dr. Armando Paez, chief of infectious diseases with Baystate Health, said it’s difficult to gauge the number of positive cases because of reduced vigilance among the public and the unreported use of at-home testing — though Baystate Medical Center in Springfield did see 40-50 patients who tested positive for the disease in a week’s span. Of those who tested positive, he said only 20% of them were admitted for treatment for the virus, with the others testing positive only after being admitted for unrelated issues.

“It’s started to pick up over the last few weeks,” Paez said. “There is definitely an increased number of cases, but it’s not as many as what we had experienced last year or in previous years.”

At Cooley Dickinson Hospital in Northampton, there has also been a notable increase in patients over the past month, according to Dr. Joanne Levin, the hospital’s medical director of infection prevention.

“It’s definitely been trending up since the end of June,” she said. “I think most of us know people who have had COVID recently and we just feel it in our community.” Even so, the number of cases is still lower than during the previous year, she said.

The rising number of cases in the Pioneer Valley reflects trends across both the state and the nation. According to the Centers for Disease Control, from Aug. 27 to Sept. 2 there was an 8.7% increase in the number of hospital admissions due to COVID-19 in the United States, and a 10.5% increase in the number of deaths related to the virus during the same time frame.

Fortunately, the recent uptick in cases coincides with the most recent COVID-19 vaccines being approved by the Food and Drug Administration. The newest approved vaccines, produced by companies Pfizer and Moderna, are meant to target the current dominant strain of COVID-19, known as XBB1.5.

“Vaccination remains critical to public health and continued protection against serious consequences of COVID-19, including hospitalization and death,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement following approval of the vaccine. “The public can be assured that these updated vaccines have met the agency’s rigorous scientific standards for safety, effectiveness and manufacturing quality.”

Paez said the vaccines are expected to be effective against the currently dominant variant, although there had been a small number of infections by a reported subvariant where efficacy may be limited.

“It’s only been a few cases of that subvariant that’s been reported in the United States,” he said. “The other good thing is that it’s only based on preliminary data, and the immune escape may not be as bad as they feared initially.”

Levin said the new vaccine is especially crucial for those over the age of 65 or with underlying conditions that make them more vulnerable to the virus’ effects.

“If you haven’t had a vaccine in the last two to four months, you’re allowed to get the new vaccine,” she advised. “If you’re planning a big travel event, you might want to get the vaccine a few weeks before you go away, depending on your risk.”

Of course, there are other ways to limit the spread of the virus — washing hands, staying at home if one is feeling sick, or wearing a mask if they worry about being in a crowded area.

“That’s very important for patients who are expected not to respond very well to the vaccine, or at least have a shorter immunity duration,” Paez said. “If you feel unwell, get tested because it might be COVID-19.”

Alexander MacDougall can be reached at amacdougall@gazettenet.com. Reporter Mary Byrne contributed to this article.