A British Columbia arbitrator has upheld a provincial policy that requires health-care workers in the province to either get vaccinated or wear a face mask during flu season.

Arbitrator Robert Diebolt's ruling says the government's policy is "a valid exercise of the employer's management rights."

The policy requires health-care workers to either get the flu vaccine each year, or wear masks while caring for patients during the flu season, which typically lasts approximately four months.

British Columbia's medical officer of health Dr. Perry Kendall welcomed the decision Thursday afternoon, saying it was "win for patients" and residents of long-term care facilities.

With the ruling upheld, Kendall said he now expects compliance to the policy to be "very high."

Three unions -- the Health Sciences Association, Hospital Employees Union and B.C. Nurses Union -- launched grievances over the policy, with the Health Sciences Association representing them in the arbitration process.

The HSA, which represents approximately 16,000 health-care workers, argued that workers had the right to make their own personal health decisions and to choose not to be vaccinated for philosophical, health or religious objections.

But Diebolt wrote in his decision Thursday that, given the seriousness of influenza, a program that increases immunization rates in the health-care setting is a reasonable policy.

Diebolt, who listened to arguments from each side of the debate over 15 days, said he was persuaded there was a rational connection between the policy and patient safety.

"It is indisputable that influenza can be a serious, even fatal, disease," Dieboldt writes in his decision.

"Immunization also indisputably provides a measure of protection to health care workers and I have found that their immunization reduces influenza transmission to patients. I have also concluded that there is some evidence to support the masking component of the Policy.

"In short, there is a real and serious patient safety issue and the Policy is a helpful program to reduce patient risk."

He noted that the policy is fair because it allows health workers who either can't get the vaccine or choose not to, to wear a mask instead.

"Health care workers do not have to immunize; they have a choice to immunize or mask during the influenza season," Diebolt writes.

Kendall said the program will have a range of options available to discipline health-care workers who do not abide by the policy, including education, engagement or termination.

However, he said the ministry expects that situations requiring termination would be "very, very rare."

There would also be some situations where workers would be accommodated and not be required to comply with the program if they have a legitimate reason why they can't have a flu shot or wear a mask, he added.

These reasons may include medical, religious or ethical reasons, as well as if their profession requires that their mouth be visible, such as a speech pathologist, Kendall said.

"In those cases, we can make accommodations," he said, noting that transparent masks could potentially be one available option.

He said the program also extends to visitors to health-care facilities, however it will work on the honour system for them.

"We will be expecting visitors who haven't had an influenza shot to pick up a mask and wear it when they're in a health-care facility," he said.

The B.C. government launched the mandatory flu shot program for health-care workers last year, saying the policy was meant to protect patients. It noted that voluntary vaccination programs weren't working, as fewer than 50 per cent of workers in some health settings were getting the shots.

HSA president Val Avery said her team was "disappointed" with Thursday's ruling.

“Our members believed they had a right to make personal health-care decisions, but this policy says that’s not the case," she said in a statement.

“We will be telling our members to comply with the new policy, or risk being fired,” she added.

She said her union was pleased that some changes were made to the policy. Previously, flu immunization status reports of employees were circulated at the workplace. Dieboldt determined that approach “was an abuse of the privacy rights of health-care workers."

As well, the original policy required health-care workers to report if other workers were not complying with the policy. That requirement was also removed as there was a risk it could create an unnecessary atmosphere of suspicion and accusation in the workplace.

It is estimated that 8,000 Canadians die from the flu or its complications every year. Bacterial pneumonia, an infection of the lungs, is the most common complication, especially in elderly people in whom it is often fatal.

A number of U.S. health-care facilities have instituted similar flu shot programs, and in 2012, the health authority in northern New Brunswick instituted a similar policy.

Other Canadian provinces may now proceed to follow suite, Kendall said.

With files from The Canadian Press and CTVNews.ca's Marlene Leung