Boards of health in four more Island towns voted unanimously this week to impose a mask mandate for indoor public spaces, and West Tisbury adopted a vaccination requirement for town employees as Covid-19 cases on the Vineyard continued to climb.

In their weekly report, Island health agents confirmed 87 new cases for the week ending Saturday, Aug. 14, the third most active week since the pandemic began. Another 57 cases have been confirmed since then -- five on Sunday, 11 on Monday, 10 on Tuesday, 22 on Wednesday and nine on Thursday.

At a press briefing Wednesday, Martha’s Vineyard Hospital officials said its emergency room capacity was being tested by a torrent of Covid and non-Covid related patients.

“The increase in cases is also coming at a very busy time for the hospital,” said hospital CEO Denise Schepici. “We’re bursting at the seams.”

Ms. Schepici said Islanders who deferred care during the pandemic, general summer colds as well as people with mild Covid-19 symptoms coming to the emergency room seeking care, were all factors the hospital’s particularly busy month.

“This is why we have been encouraging folks not to come to the emergency room unless . . . you are feeling really, really sick and you feel like it’s an emergency,” she said.

As of Wednesday, the hospital had three patients hospitalized with Covid-19 and a fourth patient under investigation showing Covid-like symptoms. A fifth Covid-positive patient was critically airlifted to Boston last week.

While hospital officials could not disclose the individual vaccination status of specific patients, they said the sickest patients were unvaccinated.

In a rare joint emergency meeting, Edgartown, Oak Bluffs and Tisbury boards of health voted unanimously Tuesday to institute a mask mandate for indoor public spaces, citing the rapid spread of the Delta variant, and Chilmark followed suit the next day. West Tisbury had adopted a mask mandate last week.

The face-covering requirement comes more than three months after local officials rescinded all Covid-19 public health regulations at the start of summer, following guidance issued by the Centers for Disease Control and Gov. Charlie Baker as positivity rates declined and vaccination rates rose.

“Despite excellent vaccination rates in Dukes county with Dukes county residents and perhaps with our visitors, we’re still seeing more cases than the local system can process in a long-term manner,” said Chilmark board of health member Matt Poole in urging the mandate. Mr. Poole is also the health agent for Edgartown.

Effective Friday, the face covering requirement applies to performance venues, food service establishments, bars, public and private transportation systems, dance venues, hotels, gyms, retail stores, houses of worship, personal service establishments and offices that are open to the public.

Establishments are required to post signs about the face covering requirement and are responsible for enforcement.

In West Tisbury, officials convened an unprecedented joint meeting of the town’s elected boards that separately hold hiring and appointing power over town workers to consider a vaccination mandate for all employees.

Six of the seven boards unanimously agreed to adopt a policy that gives West Tisbury employees, interns and volunteers until Sept. 30 to show proof of full vaccination. Only the board of assessors failed to support the vaccination mandate, splitting 1-1 between members Maria McFarland, who voted in favor, and chairman Michael Colaneri, who at first delayed calling the board to order and later voted no.

Municipal workers can seek exemptions from the vaccination mandate for medical or religious reasons only, town labor attorney Jack Collins told some 40 members of the select board, board of health, finance committee, planning board, board of assessors, library trustees and parks and recreation committee who gathered on Zoom late Wednesday afternoon.

“Everything’s on an individual basis,” Mr. Collins said, describing the process of qualifying an employee’s request for a medical exemption.

“You address that person . . . privately, [and] you give them an opportunity to present any information they have — presumably a note from a doctor that explains why it is medically they’re not suitable for this,” he said, adding: “They might have an underlying medical condition. They might be allergic to something in the vaccine, things like that. If that were the case, then you’d look and see if you could make some kind of a reasonable accommodation.”

West Tisbury health agent Omar Johnson cited the Island’s rising infection rate in his appeal for seven yes votes.

Epidemiological studies have shown that vaccines are 55 per cent effective against infections, 80 per cent effective against symptomatic infections and 90 per cent effective against hospitalizations, Mr. Johnson said.

“We need to do all that we can in the interest of public health, which as you know represents the greater interest of everyone,” the health agent said.

Explaining the process for employees who are exempt, Mr. Collins said accommodations might involve working from home, frequent Covid-19 testing or other individual arrangements depending on the worker and their duties.

Requests for religious exemptions will follow the same interactive process, with Mr. Collins cautioning town officials that court rulings have established a broad definition of religion as a “sincerely held” belief.

At worst, if an exemption-seeking worker’s duties require being with the public or other employees, Mr. Collins advised placing them on unpaid leave until the Covid-19 crisis abates.

“We’re not recommending in general that employers decided to terminate somebody in this kind of situation,” he said. “You want to give every opportunity to somebody to try to resolve any problems they have.”

There is no legal requirement to accommodate workers who object to vaccination on other than qualified medical or legal grounds, he also said.

Exemption requests will be sent through town administrator Jennifer Rand for legal review by Mr. Collins.

While saying he does support vaccinations, Mr. Colaneri said he opposes the mandate, in explaining his vote.

“To my knowledge, no one on the Vineyard has died yet — not that that’s an indicator,” he said. “I think that the mask mandate has worked well. I think individuals have a responsibility to do as much as they possibly can.”

While the split vote means that assessors workers technically are not covered by the mandate, the select board could vote to require full vaccination for anyone working at town hall, Mr. Collins said.

On a positive note, hospital officials said the rise in Covid cases had prompted an increase in the number of patients arriving at the hospital seeking a first-dose vaccine. Approximately 80 patients per day are coming to receive their first shots, after vaccination rates dropped to near-zero earlier in the summer.

Officials attributed the increase to concern among initially vaccine-hesitant people, as well as an influx of visitors, and emerging vaccine requirements by colleges and workplaces.

Hospital officials also said calls would begin going out to specific Islanders who are already eligible for a third Covid-19 vaccination shot with the Pfizer and Moderna vaccines based on compromised immune systems, and federal approval of a third shot for others is expected soon.

A second Johnson & Johnson shot has not yet been authorized, according to hospital officials.

Current eligibility is based upon the length of time between the second and third dose — which should be around eight months — as well as medical criteria, hospital officials said.

Hospital officials expected the broader third-shot vaccine rollout to closely follow rollout for the first and second shots, except with fewer supply issues.

Kate Dario contributed reporting.