Dr. Eilish Cleary says immunization clinics will continue using another vaccine, Fluviral, but if the hold on Agriflu continues, the province may have to start rationing. (CBC)

Half of New Brunswick's supply of this year's flu vaccine is on hold, pending a review by Health Canada after clumping particles were discovered in some batches in Europe.

About 50,000 doses of the Agriflu vaccine, manufactured by Novartis, have already been distributed across the province, said the province's chief medical officer of health Eilish Cleary.

But there have been no reported ill-effects to date, she said.

"There's been no health problems reported or associated with it and all indications are that it's just sort of a natural byproduct of the manufacturing," said Cleary.

'People who have had the influenza vaccine should not be unduly concerned.'—Dr. Eilish Cleary, chief medical officer of health

"People who have had the influenza vaccine should not be unduly concerned."

Still, many people are worried, said Vicki Thomas, district manager of the Victorian Order of Nurses. Several people at a Fredericton flu clinic over the weekend were asking about the recall, she said.

"And so we reassured clients that we weren't using that product, that we were using another product, called Fluviral."

May have to ration

Immunization clinics across the province, which are kicking into high gear, will continue to operate using Fluviral until the Health Canada review is complete, said Cleary.

But Agriflu represents about half of the province's supply of 260,000 doses, she said.

If the hold on Agriflu continues for several weeks, the province may have to look at rationing the shots, giving priority to those most at risk, Cleary said.

Health Canada is expected to give an update on its review within the next few days.

The Public Health Agency of Canada recommended on Oct. 26 that health care professionals in possession of Agriflu vaccines refrain from using them until the review is complete.

Health Canada also asked Novartis to voluntarily suspend distribution of the vaccines in Canada as a precaution, pending the review.

Health Canada vigorously reviewed Agriflu for safety and effectiveness before it was authorized for use in Canada, according to a news release. Clumping is common in vaccines, it states.

"Health Canada has previously seen such particles before in other vaccines and has observed no impact on their safety or effectiveness," according to the release.

Agriflu has also been temporarily pulled from use in several European countries.