Eggs are the reason for ineffective flu vaccines

The production of flu vaccines isn’t perfect, and there’s one unexpected factor behind that -- eggs.

A new study published in PNAS suggests the reason why last winter’s flu vaccine was only moderately effective was because of chicken eggs.

According to STAT, flu vaccines are primarily developed from antigens grown in eggs from hens. Before being put into the vaccine, those antigens are inactivated or killed.

But once they’re growing in the eggs, those human vaccine strains can often mutate.

And the problem is, last year’s H3N2 vaccine had a mutation.

Leading humans and ferrets exposed to the vaccine to produce antibodies that weren’t effective in fighting that type of flu.

And STAT suggests this year’s flu vaccine has that same H3N2 component.

The director of the World Health Organization’s Collaborating Centres for influenza in Australia told STAT, “We need to do a lot to improve existing vaccines. And getting away from eggs would be very valuable.”

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