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Source: https://www.cbc.ca/news/canada/montreal/quebec-vaccine-effectiveness-second-doses-1.5918449
Quebec's bet on delaying second dose of COVID-19 vaccine is paying off, early data show
Preliminary results show strong immunity in health-care workers and long-term care residents after one dose
Sean Gordon ? CBC News ? Posted: Feb 18, 2021 1:06 PM ET | Last Updated: 5 hours ago
When the Quebec government confirmed in mid-January it would delay the second of two doses of the COVID-19 vaccines for up to 90 days, a debate erupted among scientists over the wisdom of the decision.
Now there is data to settle, or at least tamp down, the argument. Based on preliminary figures compiled by the Comit? sur l'immunisation pour le Qu?bec, it appears to have been the right move.
The data show the vaccines to be 80 per cent effective after 14 days in younger vaccinated populations (primarily health-care workers) and after three weeks among the residents of CHSLDs, who tend to be much older and sicker.
In other words, a vaccinated person has an 80 per cent lower likelihood of contracting COVID-19 than an unvaccinated person between two and three weeks after receiving the first shot.
Both Pfizer-BioNTech and Moderna have issued protocols on administering a second dose at a precise interval (21 and 28 days, respectively) based on clinical studies. That's also the basis on which they've been approved by Health Canada.
But Quebec's early numbers, which the CIQ said align with results observed in British Columbia and Israel, suggest it's eminently defensible to delay the booster shot longer in the context of a vaccine shortage...
Quebec's bet on delaying second dose of COVID-19 vaccine is paying off, early data show
Preliminary results show strong immunity in health-care workers and long-term care residents after one dose
Sean Gordon ? CBC News ? Posted: Feb 18, 2021 1:06 PM ET | Last Updated: 5 hours ago
When the Quebec government confirmed in mid-January it would delay the second of two doses of the COVID-19 vaccines for up to 90 days, a debate erupted among scientists over the wisdom of the decision.
Now there is data to settle, or at least tamp down, the argument. Based on preliminary figures compiled by the Comit? sur l'immunisation pour le Qu?bec, it appears to have been the right move.
The data show the vaccines to be 80 per cent effective after 14 days in younger vaccinated populations (primarily health-care workers) and after three weeks among the residents of CHSLDs, who tend to be much older and sicker.
In other words, a vaccinated person has an 80 per cent lower likelihood of contracting COVID-19 than an unvaccinated person between two and three weeks after receiving the first shot.
Both Pfizer-BioNTech and Moderna have issued protocols on administering a second dose at a precise interval (21 and 28 days, respectively) based on clinical studies. That's also the basis on which they've been approved by Health Canada.
But Quebec's early numbers, which the CIQ said align with results observed in British Columbia and Israel, suggest it's eminently defensible to delay the booster shot longer in the context of a vaccine shortage...