some critics said granting an extension two days before an expiry date inspires little trust. “doses just a couple days away from the manufacturer’s expiry magically got an extra month of life,” university of ottawa professor of law amir attaran said on social media, noting that the world health organization, in a may 17 statement , recommended that any covid-19 vaccine that has passed its expiry date should not be administered. “expiry dates do not affect the safety of the vaccine,” the agency noted, “rather are related to the potency or amount of protection the vaccine gives.”
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health canada, in a statement to the post, said its authorization of an extended expiry date isn’t in conflict with the who’s position.
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“if this is an evidence-based decision (and i’m assuming it is) then the key will be to frame the explanation in a way that is transparent and retains confidence,” timothy caulfield, canada research chair in health law and policy at the university of alberta, said in an email to the national post sunday.
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the doses set to expire were small, relatively speaking (ontario received a shipment of 254,500 astrazeneca doses the week of may 17). but the extended shelf life comes as pressure mounts to accelerate second doses of covid vaccines amid the growing threat of variants. ontario’s covid-19 science advisory table is warning ontario premier doug ford that the variant that first emerged in india, known as b.1.617, presents “a significant unknown.”
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a study published last week by public health england found that two doses of astrazeneca vaccine were 60 per cent effective against b.1.617, while two doses of pfizer-biontech gave 88 per cent protection against symptomatic disease.