Projections of the transmission of the Omicron variant for Toronto,Ontario,and Canada using surveillance data following recent changes in testing policies  

作　　者：Pei Yuan Elena Aruffo Yi Tan Liu Yang Nicholas HOgden Aamir Fazil Huaiping Zhu 

机构地区：[1]Laboratory of Mathematical Parallel Systems(LAMPS),Centre for Diseases Modelling,Department of Mathematics and Statistics,York University,Toronto,ON,Canada [2]Public Health Agency of Canada(PHAC),Ottawa,ON,Canada

出　　处：《Infectious Disease Modelling》2022年第2期83-93,共11页传染病建模（英文）

基　　金：supported by the Natural Sciences and Engineering Research Council of Canada and Public Health Agency of Canada OMNI one health modelling network for the Emerging Infectious Diseases Modelling Initiative;the Canadian Institutes of Health Research(CIHR)Canadian COVID-19 Math Modelling Task Force,and by York Research Chair Program.

摘　　要：At the end of 2021,with the rapid escalation of COVID19 cases due to the Omicron variant,testing centers in Canada were overwhelmed.To alleviate the pressure on the PCR testing capacity,many provinces implemented new strategies that promote self testing and adjust the eligibility for PCR tests,making the count of new cases underreported.We designed a novel compartmental model which captures the new testing guidelines,social behaviours,booster vaccines campaign and features of the newest variant Omicron.To better describe the testing eligibility,we considered the population divided into high risk and non-highrisk settings.The model is calibrated using data from January 1 to February 9,2022,on cases and severe outcomes in Canada,the province of Ontario and City of Toronto.We conduct analyses on the impact of PCR testing capacity,self testing,different levels of reopening and vaccination coverage on cases and severe outcomes.Our results show that the total number of cases in Canada,Ontario and Toronto are 2.34(95%CI:1.22e3.38),2.20(95%CI:1.15e3.72),and 1.97(95%CI:1.13e3.41),times larger than reported cases,respectively.The current testing strategy is efficient if partial restrictions,such as limited capacity in public spaces,are implemented.Allowing more people to have access to PCR reduces the daily cases and severe outcomes;however,if PCR test capacity is insufficient,then it is important to promote self testing.Also,we found that reopening to a pre-pandemic level will lead to a resurgence of the infections,peaking in late March or April 2022.Vaccination and adherence to isolation protocols are important supports to the testing policies to mitigate any possible spread of the virus.

关 键 词：PCR testing SELF-TESTING Booster dose Social behavior Mathematical model COVID-19 Omicron Exit strategy 

分 类 号：R373[医药卫生—病原生物学] R181.3[医药卫生—基础医学]