TY - JOUR
T1 - Effect of the incremental protection of previous infection against Omicron infection among individuals with a hybrid of infection- and vaccine-induced immunity
T2 - a population-based cohort study in Canada
AU - Wu, Shishi
AU - Li, Yanhong
AU - Mishra, Sharmistha
AU - Bodner, Korryn
AU - Baral, Stefan
AU - Kwong, Jeffrey C.
AU - Wei, Xiaolin
N1 - Funding Information:
This study was supported by the Ontario Health Data Platform (OHDP), a Province of Ontario initiative to support Ontario's ongoing response to COVID-19 and its related impacts. This analysis was also supported by Institute for Clinical Evaluative Studies (ICES), which is funded by an annual grant from the Ontario Ministry of Health (MOH) and the Ministry of Long-Term Care (MLTC). We were not paid to write this manuscript by any pharmaceutical company or agency. SW is supported by the Dalla Lana School Implementation Science Interdisciplinary Cluster. XW is supported as the Dalla Lana Chair in Global Health Policy at the University of Toronto. XW declares funding from the Canadian Institutes of Health Research. JK is supported by a Clinician-Scientist award from the Department of Family and Community Medicine at the University of Toronto. SM is supported by a Tier 2 Canada Research Chair in Mathematical Modeling and Program Science. The publication of the study is supported by the Dalla Lana School of Public Health at the University of Toronto through the Implementation Science INterdisciplinary Cluster.
Funding Information:
This study was supported by the Ontario Health Data Platform (OHDP), a Province of Ontario initiative to support Ontario's ongoing response to COVID-19 and its related impacts. The opinions, results and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by the OHDP, its partners, or the Province of Ontario is intended or should be inferred. We would like to acknowledge Public Health Ontario for access to case-level data from Public Health Case and Contact Management Solution (CCM) and COVID-19 laboratory data, as well as assistance with data interpretation. Parts of this material are based on data and information compiled and provided by CIHI and the Ontario Ministry of Health. The analyses, conclusions, opinions and statements expressed herein are solely those of the authors and do not reflect those of the funding or data sources. No endorsement is intended or should be inferred. We thank the Toronto Community Health Profiles Partnership for providing access to the Ontario Marginalization Index. Parts of this material are based on data compiled, provided and adapted from Statistics Canada, Census, 2016. This does not constitute an endorsement by Statistics Canada of this product. We also acknowledge and thank ICES staff, Maria Koh, Daniella Barron, and Haley Golding, for cleaning and preparing the data. ICES is an independent, non-profit research institute whose legal status under Ontario's health information privacy law allows it to collect and analyze health care and demographic data, without consent, for health system evaluation and improvement. The authors are grateful to staff of Ontario's public health units who are responsible for COVID-19 case and contact management and data collection within CCM. We would also like to thank the Global Implementation Science Cluster for covering the publication fee. The authors are also grateful to the Ontario residents without whom this research would be impossible.
Publisher Copyright:
© 2022 The Authors
PY - 2023/2
Y1 - 2023/2
N2 - Objectives: We examined the incremental protection and durability of infection-acquired immunity against Omicron infection in individuals with hybrid immunity in Ontario, Canada. Methods: We followed up 6 million individuals with at least one multiplex reverse transcriptase–polymerase chain reaction test before November 21, 2021, until an Omicron infection. Protection via infection-acquired immunity was assessed by comparing Omicron infection risk between previously infected individuals and those without documented infection under different vaccination scenarios and stratified by time since the last infection or vaccination. Results: A previous infection was associated with 68% (95% CI 61-73) and 43% (95% CI 27-56) increased protection against Omicron infection in individuals with two and three doses, respectively. Among individuals with two-dose vaccination, the incremental protection of infection-induced immunity decreased from 79% (95% CI 75-81) within 3 months after vaccination or infection to 27% (95% CI 14-37) at 9-11 months. In individuals with three-dose vaccination, it decreased from 57% (95% CI 50-63) within 3 months to 37% (95% CI 19-51) at 3-5 months after vaccination or infection. Conclusion: Previous SARS-CovV-2 infections provide added cross-variant immunity to vaccination. Given the limited durability of infection-acquired protection in individuals with hybrid immunity, its influence on shield-effects at the population level and reinfection risks at the individual level may be limited.
AB - Objectives: We examined the incremental protection and durability of infection-acquired immunity against Omicron infection in individuals with hybrid immunity in Ontario, Canada. Methods: We followed up 6 million individuals with at least one multiplex reverse transcriptase–polymerase chain reaction test before November 21, 2021, until an Omicron infection. Protection via infection-acquired immunity was assessed by comparing Omicron infection risk between previously infected individuals and those without documented infection under different vaccination scenarios and stratified by time since the last infection or vaccination. Results: A previous infection was associated with 68% (95% CI 61-73) and 43% (95% CI 27-56) increased protection against Omicron infection in individuals with two and three doses, respectively. Among individuals with two-dose vaccination, the incremental protection of infection-induced immunity decreased from 79% (95% CI 75-81) within 3 months after vaccination or infection to 27% (95% CI 14-37) at 9-11 months. In individuals with three-dose vaccination, it decreased from 57% (95% CI 50-63) within 3 months to 37% (95% CI 19-51) at 3-5 months after vaccination or infection. Conclusion: Previous SARS-CovV-2 infections provide added cross-variant immunity to vaccination. Given the limited durability of infection-acquired protection in individuals with hybrid immunity, its influence on shield-effects at the population level and reinfection risks at the individual level may be limited.
KW - COVID-19
KW - COVID-19 vaccines
KW - Infection-acquired immunity
KW - Infectious disease epidemiology
KW - Reinfection
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U2 - 10.1016/j.ijid.2022.11.028
DO - 10.1016/j.ijid.2022.11.028
M3 - Article
C2 - 36455812
AN - SCOPUS:85144883233
SN - 1201-9712
VL - 127
SP - 69
EP - 76
JO - International Journal of Infectious Diseases
JF - International Journal of Infectious Diseases
ER -