Italy, Germany and Switzerland have suspended distribution of some Novartis flu vaccine, and in the case of Germany recalled some lots of vaccine, after the clumping issue came to light.
A statement from Novartis said finding minute clumps of virus protein in vaccines is not unusual. They said their vaccines passed quality inspections and so far this year there have been no signals of adverse events associated with use of the vaccine.
"The aggregate proteins are predominantly influenza virus-derived (mainly hemagglutinin), all normal and necessary components of influenza vaccines," the company's statement said. "Aggregation of these proteins is not unusual in vaccines manufacturing."
Hemagglutinin is the protein on the outside of flu viruses that locks onto cells in the human respiratory tract to start the process of infection. Flu vaccines are designed to provoke the immune system to produce antibodies to hemagglutinin to protect against infection.
In fact, this isn't the first time protein clumping has disrupted Canada's flu vaccine supply.
During the 2009 pandemic, there was a delay in delivery of unadjuvanted vaccine for pregnant women when GlaxoSmithKline, Canada's pandemic vaccine supplier, found visible protein aggregation in some of the vaccine.
Adjuvants are compounds that boost the response a vaccine generates. Canada used adjuvanted vaccine during the pandemic, but bought some unboosted product for pregnant women as a precaution.
Novartis makes only about 20 per cent of Canada's annual flu vaccine purchase. GlaxoSmithKline makes the bulk of Canada's seasonal flu vaccine, though a variety of other suppliers have a share of the Canadian market.
Still, because of the way vaccine orders are placed, the hold on Novartis vaccine could put some provinces and territories in a position where they face a temporary vaccine shortfall, just at the time when flu shot programs are getting underway, Gully admitted.
He said Health Canada hopes there is a rapid resolution of the situation. But if provinces or territories have a problem with supply, efforts will be made to share across jurisdictions, he said.
Both Fluad and Agriflu are sold in single-dose formulations, pre-loaded into a syringe.
Fluad contains an adjuvant and is licensed for use in people 65 and older. Older adults do not mount a good response to flu vaccine and the inclusion of an adjuvant is an effort to improve the protection (sic) they get from flu shots.
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