New Brunswick Public Health officials have identified the specific batch of a flu vaccine and are ordering the disposal of remaining doses after three people became ill shortly after receiving the shot.
The identified batch contained about 85,000 doses. Providers will not administer any remaining vaccine from the batch.
The "adverse effects" were reported in three adults who received the vaccine between Oct. 2 and 20, according to a news release. Officials confirmed the situation on Saturday.
Dr. Cristin Muecke, the province's deputy chief medical officer, said New Brunswickers who have yet to get vaccinated against influenza should get the shot.
"The risk of experiencing a severe adverse event remains extremely low and anyone who received a flu vaccine more than 10 days ago without an adverse reaction should not be concerned," Muecke said in a statement.
The source of the health complications remains under investigation and it has not been determined if the vaccine was the cause.
Public Health says symptoms occurred after about seven days and included sustained numbness or weakness of the face and limbs.
Dr. Caroline Quash, an epidemiologist at Sainte-Justine Hospital in Montreal, said reactions included the Guillain-Barré syndrome, transverse myelitis and Bell's palsy.
Quash said Bell's palsy is not associated with reactions to the influenza vaccination, leaving two cases which could be potentially linked. She said it's important not to jump to conclusions.
"The cause has not been established," she told Radio-Canada. "We need to see if there's other reasons that can explain the emergence of these two syndromes."
The province was able to identify the specific batch through its electronic health record system.
The batch was also distributed in Quebec and other parts of the country, and the Public Health Agency of Canada has been notified.
There have been no reports so far of similar reactions outside New Brunswick.
Quash said the batch has not been removed by Health Canada or other provinces.
New Brunswick has received 420,000 doses of influenza vaccine this year— a 26 per cent increase from 2019.
Public Health says anyone experiencing neurological symptoms should seek advice from their health-care provider and let them know if they received the flu shot in the last 10 days.
GlaxoSmithKline (GSK) Canada said in a statement to Radio-Canada Sunday evening that it was made aware of some undesirable side effects in a batch of vaccine Friday.
The company is hoping to be in touch with public health officials to get more information. In the meantime, it said it is doing an internal investigation and will share results with Public Health.