A hospital system in Ontario, Canada, has apologized after the names of staff members who are not vaccinated against COVID-19 were accidentally leaked.

The human resources department at The Ottawa Hospital sent a system-generated email to unvaccinated staffers last week, inviting them to participate in an education module on the shots. The email did not blind carbon copy their email addresses, according to multiple media reports .

Instead, the staffers email addresses appeared in full in the To section and were visible to everyone else on the list.

The email was immediately recalled and all copies were deleted, a spokesperson told HuffPost via an emailed statement on Wednesday. An apology and explanation was sent to the staff members affected.

Employees of the hospital are expected to be vaccinated against COVID-19, per the statement. They should have received their first dose by Sept. 7, The Ottawa Citizen reported .

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, the hospital said in its statement.

Its unclear exactly how many hospital staff were named in the email, and therefore are unvaccinated. But CTV News Ottawa , citing a hospital source, said it could be as many as 391 out of 11,600 total staff members.