OTTAWA -- The Ottawa Hospital says it has apologized to employees whose names were mistakenly visible on a mass email to unvaccinated staff last week.

A letter from the hospital's human resources office, obtained by CTV News Ottawa, said a system-generated email sent Sept. 8 to "employees who have declined the COVID-19 vaccination" included staff email addresses in the "To" section and not as blind carbon copies.

The original email, which CTV News Ottawa has not seen, was an invitation to complete an educational module about COVID-19 vaccination.

In a statement, the Ottawa Hospital said the issue was addressed promptly.

"This past week, an email was sent from one of our software systems to a list of unvaccinated staff members, inviting them to complete a vaccine education session. The staff names were unfortunately visible," the statement said. "The email was immediately recalled and all copies were deleted. An apology and explanation was sent to the staff members affected. TOH’s Information and Privacy Office investigated the matter and reported it to the Information and Privacy Commissioner." 

The hospital did not confirm how many staff members were affected, but a source told CTV News Ottawa there were 391 names on the list.

In the email to staff acknowledging the breach, the hospital said they contacted IT services to remove the original email from all inboxes, notified the hospital's privacy office, asked anyone who forwarded the email to personal accounts to delete it, conducted an investigation into how this breach happened, and contacted people who were affected.

In its statement to CTV News, the Ottawa Hospital said it expects staff to be vaccinated.

"The Ottawa Hospital expects every member of our organization to receive the vaccine, as it is an important step to ensuring the safety of everyone in our community. Educating our unvaccinated staff is an important step in that journey," the statement said.

Ottawa Hospital staff were required to receive their first dose by Sept. 7. They must have their second dose by Oct. 15.

"Health-care workers have worked tirelessly to protect our communities throughout the pandemic, and they deserve protection and support to enable them to do their jobs safely, and to the best of their abilities," TOH said.