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This article is a preprint and has not been certified by peer review
Posted July 03, 2021.
doi: https://doi.org/10.1101/2021.06.28.21259420
Authors: Sharifa Nasreen PhD1, Siyi He MSc1, Hannah Chung MPH1, Kevin A. Brown PhD1,2,3, Jonathan B. Gubbay MD MSc3, Sarah A. Buchan PhD1,2,3,4, Sarah E. Wilson MD MSc1,2,3,4, Maria E. Sundaram PhD1,2, Deshayne B. Fell PhD1,5,6, Branson Chen MSc1, Andrew Calzavara MSc1, Peter C. Austin PhD1,7, Kevin L. Schwartz MD MSc1,2,3, Mina Tadrous PharmD PhD1,8, Kumanan Wilson MD MSc9, and Jeffrey C. Kwong MD MSc1,2,3,4,10,11 on behalf of the Canadian Immunization Research Network (CIRN) Provincial Collaborative Network (PCN) Investigators
ABSTRACT:
Objectives: To estimate the effectiveness of BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and ChAdOx1 (AstraZeneca) vaccines against symptomatic SARS-CoV-2 infection and severe outcomes (COVID-19 hospitalization or death) caused by the Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) variants of concern (VOCs) during December 2020 to May 2021.
Methods: We conducted a test-negative design study using linked population-wide vaccination, laboratory testing, and health administrative databases in Ontario, Canada.
Results: Against symptomatic infection caused by Alpha, vaccine effectiveness with partialvaccination (≥14 days after dose 1) was higher for mRNA-1273 than BNT162b2 and ChAdOx1.Full vaccination (≥7 days after dose 2) increased vaccine effectiveness for BNT162b2 andmRNA-1273 against Alpha. Protection against symptomatic infection caused by Beta/Gamma was lower with partial vaccination for ChAdOx1 than mRNA-1273. Against Delta, vaccine effectiveness after partial vaccination tended to be lower than against Alpha for BNT162b2 and mRNA-1273, but was similar to Alpha for ChAdOx1. Full vaccination with BNT162b2 increased protection against Delta to levels comparable to Alpha and Beta/Gamma. Vaccine effectiveness against hospitalization or death caused by all studied VOCs was generally higher than for symptomatic infection after partial vaccination with all three vaccines.
Conclusions: Our findings suggest that even a single dose of these 3 vaccine products provide good to excellent protection against symptomatic infection and severe outcomes caused by the 4 currently circulating variants of concern, and that 2 doses are likely to provide even higher protection.
Posted July 03, 2021.
doi: https://doi.org/10.1101/2021.06.28.21259420
Authors: Sharifa Nasreen PhD1, Siyi He MSc1, Hannah Chung MPH1, Kevin A. Brown PhD1,2,3, Jonathan B. Gubbay MD MSc3, Sarah A. Buchan PhD1,2,3,4, Sarah E. Wilson MD MSc1,2,3,4, Maria E. Sundaram PhD1,2, Deshayne B. Fell PhD1,5,6, Branson Chen MSc1, Andrew Calzavara MSc1, Peter C. Austin PhD1,7, Kevin L. Schwartz MD MSc1,2,3, Mina Tadrous PharmD PhD1,8, Kumanan Wilson MD MSc9, and Jeffrey C. Kwong MD MSc1,2,3,4,10,11 on behalf of the Canadian Immunization Research Network (CIRN) Provincial Collaborative Network (PCN) Investigators
ABSTRACT:
Objectives: To estimate the effectiveness of BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and ChAdOx1 (AstraZeneca) vaccines against symptomatic SARS-CoV-2 infection and severe outcomes (COVID-19 hospitalization or death) caused by the Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) variants of concern (VOCs) during December 2020 to May 2021.
Methods: We conducted a test-negative design study using linked population-wide vaccination, laboratory testing, and health administrative databases in Ontario, Canada.
Results: Against symptomatic infection caused by Alpha, vaccine effectiveness with partialvaccination (≥14 days after dose 1) was higher for mRNA-1273 than BNT162b2 and ChAdOx1.Full vaccination (≥7 days after dose 2) increased vaccine effectiveness for BNT162b2 andmRNA-1273 against Alpha. Protection against symptomatic infection caused by Beta/Gamma was lower with partial vaccination for ChAdOx1 than mRNA-1273. Against Delta, vaccine effectiveness after partial vaccination tended to be lower than against Alpha for BNT162b2 and mRNA-1273, but was similar to Alpha for ChAdOx1. Full vaccination with BNT162b2 increased protection against Delta to levels comparable to Alpha and Beta/Gamma. Vaccine effectiveness against hospitalization or death caused by all studied VOCs was generally higher than for symptomatic infection after partial vaccination with all three vaccines.
Conclusions: Our findings suggest that even a single dose of these 3 vaccine products provide good to excellent protection against symptomatic infection and severe outcomes caused by the 4 currently circulating variants of concern, and that 2 doses are likely to provide even higher protection.
