It’s time to halt AstraZeneca shots in Canada, except for people 40 or older in hotspots, says Andrew Morris, a doctor on Ontario’s COVID-19 science advisory table
'What concerns me is there is confusion out there that one dose gives you enough protection that you can start to change behaviour, and there is no evidence to suggest that'
With AstraZeneca delays, and 36 million doses of Pfizer and Moderna scheduled to come, mixing for potentially hundreds of thousands of people may become unavoidable
