I'll start with this. Last week, NACI recommended that either the AstraZeneca/Covishield COVID-19 vaccine or an mRNA vaccine may be offered for the subsequent dose in a series started with the AstraZeneca/Covishield COVID-19 vaccine and that the previous dose should be counted and the series need not be restarted.
NACI made this recommendation at the time, informed by several studies from the international landscape, one from Spain, one from the United Kingdom and one from Germany, all of which showed that when you provide an mRNA vaccine after an AstraZeneca vaccine, it is safe. There were actually multiple intervals studied—four weeks and also eight to twelve weeks. At any of those intervals studied, overall the mixed schedule was found to be safe.
They looked at immune response data from that study from Spain as well, which showed that you do, in fact, boost the immune response when the mRNA vaccine is provided after the AstraZeneca vaccine.
Since that time, there have been several studies that have also come out from Germany, looking at the immune response, that replicate that finding as well, that you get a good, strong boost to the immune response when you follow AstraZeneca vaccine with Pfizer.
That was underpinning NACI's recommendations. They had seen studies from multiple countries looking at multiple schedules, looking at safety and now also the immune response, that have demonstrated that this is a strategy that can be used. Provinces and territories are now looking at this and how they integrate that into their second dose approaches across the country.
Thank you.