Health Canada has lifted its hold on Novartis flu vaccines, saying they are safe to use.
Provinces and territories that have bought Novartis vaccines for this year's flu shot campaigns can now resume use of the products, the department said in a statement.
The decision follows a risk assessment conducted by Health Canada, using information gathered from European regulatory agencies and the company.
"None of the information reviewed indicated a safety issue," Health Canada said in the statement.
The Novartis vaccines, sold here under the brand name Fluad and Agriflu, make up a total of 20 per cent of Canada's combined flu vaccine purchase this year. GlaxoSmithKline has the lion's share of the national purchase, 57 per cent. Sanofi Pasteur and AstraZeneca make up the rest, with 20 per cent and three per cent respectively.
The statement said Health Canada and the Public Health Agency of Canada will work with Novartis to monitor the safety and effectiveness of the vaccines. "Should a safety concern be identified, immediate and appropriate action will be taken," it said.
The decision to clear the Novartis vaccines for use means provinces like Saskatchewan that have had to cancel flu clinics will be able to resume their normal flu vaccination efforts. Saskatchewan and Prince Edward Island received most of their vaccine this year from Novartis.
Health Canada issued a halt-use order on the Novartis vaccines last Friday after several European countries stopped using Fluad and Agrippal, the name Agriflu is sold under in Europe.
The situation started when Novartis told the Italian regulatory agency that it had found a higher-than-normal level of protein aggregates in one batch of vaccine made at its plant in Siena, Italy. Protein aggregates are tiny bits of the killed influenza viruses that are used to make flu vaccine.
A Novartis senior executive said the company held back the affected lot and looked for but didn't find the problem in other batches made at the Italian facility. The Novartis vaccine that Canada buys is made at the Siena plant.
Normally the viral proteins in flu vaccine are in a suspension and are not visible to the naked eye. But from time to time they fall out of suspension and can be seen.
It is not uncommon, nor is it a sign that there is something wrong with the vaccine, Dr. Vas Narasimhan, the global head of vaccines development for Novartis Vaccines and Diagnostics, told The Canadian Press in an interview Tuesday.
"There are no contaminants in the vaccine," Narasimhan insisted. "These aggregates are formed by proteins that are expected to be in the vaccine, predominantly hemagglutinin and neuraminidase, which are the two antigens that we're using to stimulate the immune response."
Hemagglutinin and neuraminidase are proteins that sit on the outer shell of a flu virus. Flu vaccines are designed to induce antibodies to these proteins so that if an immunized person comes in contact with influenza, those antibodies should kick into gear to prevent infection.
Narasimhan said so far this season an estimated two million doses of the vaccines have been administered and there have been no signs of unexpected adverse events associated with their use.
The Public Health Agency of Canada is advising people who administer flu shots to allow the vaccine to come to room temperature before use. They also say the products should be shaken and checked for any white floating material before they are injected, though they added that material is not uncommon and doesn't pose a health risk.