GREENFIELD — Health officials seemed cautiously optimistic following the mayor’s Wednesday announcement rescinding the mask mandate for city offices and businesses, effective Monday.

“Our numbers dropped,” Health Director Jennifer Hoffman told the Board of Health Wednesday evening. “It could be attributed to many different things, but overall, we’re doing good with COVID.”

She reported that the city had 40 positive COVID-19 cases in October, compared to 115 cases in September.

“Some of it we can attribute to, I feel, wearing masks in the community, because the vaccination rate is only 64% in Greenfield,” Hoffman said. About 73% of residents have received their first dose of the vaccine.

As of Wednesday, the city has nine positive cases, of which four were among vaccinated individuals, she said.

She noted the highest rate of COVID-19 is among individuals between the ages of 30 and 39 years old, followed by 20 to 29 and then 40 to 49.

“So basically, 20 to 49 (years old) is the range of people getting COVID, which is the same population that … isn’t as highly vaccinated,” Hoffman said.

Both Massachusetts and Franklin County are still considered high risk, she noted, with the average daily incident rate at 18.6% and 10.2%, respectively.

Board of Health Chair Nancee Bershoff said she expressed her concern for the coming winter months to Mayor Roxann Wedegartner in advance of her decision to lift the mask mandate.

“We’re going to be indoors more at the end of the … warm weather season,” Bershoff said. “I’m concerned. On the other hand, I see that cases are dropping all over. My hope is that it will continue. My hope is that if we get a bump during the holidays, it won’t be much and we will continue to see a relatively low hospitalization rate.”

Board of Health member Kelly Dixon asked if there is any particular system for monitoring or re-evaluating the COVID-19 situation.

The board discussed the possibility of continuing to use hospitalization rates as a potential metric.

“We do follow hospitalizations and … people going through the (emergency room),” Hoffman said, noting that patients are often transferred from Baystate Franklin Medical Center in Greenfield to Springfield’s Baystate Medical Center due to capacity limits. “What we do follow is how many people go into the unit, their length of stay, and how many are unvaccinated and not vaccinated. … We do notice the people going into the hospital are sicker for longer.”

Still, she said she isn’t sure how reliable it would be to monitor admission rates as a marker for what is going on in the community, given that many people are sent home to monitor their symptoms.

Hoffman said she opts instead to look at the incident rate and the spread. She used a recent cluster involving 140 individuals from across several jurisdictions as an example.

“Not everyone is positive, but we have to watch that,” she said.

The cluster stemmed from an athletic event outside of Greenfield — and most involved aren’t connected to the city.

“We look at community spread,” Hoffman said.

Reporter Mary Byrne can be reached at mbyrne@recorder.com or 413-930-4429. Twitter: @MaryEByrne.