Outbreaks of COVID-19 within Maine’s hospitals were cut dramatically after vaccines for the disease became widely available this spring, but unvaccinated employees and visitors have continued to drive outbreaks, contributing to staffing shortages and resulting in at least one death from the disease.

There have been 13 outbreaks within Maine’s hospitals since March 1 resulting in 45 patients and 142 staff members becoming infected, according to data obtained from the Maine Center for Disease Control and Prevention. The agency attributed one person’s death at Waldo County General in Belfast to an outbreak there this summer, though it did not say if it was a patient or hospital employee.

“The data make a good case for why we want everybody vaccinated,” said Dr. Dora Anne Mills, chief health improvement officer at MaineHealth, the state’s largest hospital network and parent entity to the state’s largest hospital, Maine Medical Center in Portland. “We know some of our outbreaks are related to unvaccinated health care workers, others from unvaccinated patients.”

The Maine CDC defines an outbreak as having three or more confirmed COVID-19 cases in a facility in a 14-day period.

Outbreaks have an even larger impact on hospital staffing than the numbers suggest because staffers who come into contact with infected colleagues have to quarantine, and unvaccinated staffers often have to quarantine longer than their vaccinated colleagues, notes Dr. James Jarvis, physician incident commander for Northern Light Healthcare, parent entity to Eastern Maine Medical Center in Bangor.

The Bangor hospital had an outbreak during the winter surge that affected 63 staff and 14 patients. At one point, he said, the nine-hospital Northern Light system had more than 500 staffers out because they either had COVID-19 or had been exposed to someone who did.

“When staff are involved in an outbreak, it usually has to do with either community spread – because we also have to go shopping and do things within our communities – or a failure to maintain the personal protective equipment we have in place,” Jarvis said, adding that most individuals involved have been unvaccinated.

“We have required vaccinations for health care workers for a very long time because we don’t want staffers to spread disease to patients or each other, and this is just adding one more because this is a new disease,” Jarvis added.

Vaccine mandates have become a political issue in the United States, with Ohio considering repealing requirements for schoolchildren to get vaccinated for measles, smallpox and other deadly diseases. In Maine, some health care workers have resigned rather than comply with a vaccination mandate for hospital and long-term care staff announced by Gov. Janet Mills on Aug. 12. It will be enforced starting Oct. 29.

It wasn’t clear how Maine compares to the rest of the country in terms of hospital outbreak numbers. The data is not commonly posted by individual states, including Maine.

CDC Director Dr. Nirav Shah said the vaccination requirements aim to protect hospital workforces, and that hospital clinicians tell him they have had a net positive effect because the number of staffers who have had to leave work because they were infected or exposed is much larger than the number who have resigned over the mandate.

“Our health care workforce in Maine is fragile and understaffed as it is, so an outbreak in a small hospital in, say, Millinocket that takes out two of their four ICU nurses could functionally take down the intensive-care unit,” Shah said in an interview Wednesday. “It’s about force protection and the protection of the patients themselves, because we want them all to stay healthy.”

Northern Light has had 120 resignations because of the vaccine requirement, Jarvis said, but has seen the number of staffers unavailable because they are infected or quarantining fall from over 500 during the winter surge to about 150 Wednesday. He said 97 percent of the staff are now vaccinated against COVID-19.

Central Maine Medical Center in Lewiston, however, has had to curtail some services because of staffing shortages blamed in part on vaccine-related resignations. Its parent entity, Central Maine Health Care, has asked for a mandatory testing option for staff in lieu of vaccinations, a position not taken by the other hospital networks.

The data also indicates vaccines have reduced the impact of outbreaks when they do happen.

Before March, there had been 15 hospital outbreaks involving 84 patients and 234 staff members. Seven people died in the eight months between the first of those outbreaks in June 2020 and the last in February 2021. Since March 1, when hospital workers who came into contact with patients could have been fully vaccinated, only one person has died in an outbreak.

“We still have outbreaks – we will always have outbreaks – but the size of those outbreaks is structurally a lot different from the pre-vaccination era,” Shah said.

The largest single hospital outbreak since vaccines were available took place at Maine Medical Center between July and September, with 46 staff and nine patients infected.

Waldo County General’s outbreak in August and September was the second largest, involving 31 staffers but no patients. It resulted in the state’s only vaccine-era hospital outbreak death.

Smaller outbreaks since March occurred at EMMC, Southern Maine Health Care Medical Center in Biddeford, Maine Coast Memorial in Ellsworth, A.R. Gould in Presque Isle, Penobscot Bay Medical Center in Rockport, St. Mary’s in Portland, the Togus Veterans Administration hospital in Augusta, Charles Dean Hospital in Greenville and the Dorothea Dix Psychiatric Center in Bangor.