SARS-CoV-2 血清流行率在加拿大的演变：2020-2023 年的时间序列研究。
The evolution of SARS-CoV-2 seroprevalence in Canada: a time-series study, 2020-2023.
机构信息
COVID-19 Immunity Task Force (Murphy, Swail, Jain, Evans, Oxlade, Mazer, Buckeridge), School of Population and Global Health, McGill University, Montréal, Que.; Department of Community Health and Epidemiology (Anderson, Behl), University of Saskatchewan; Saskatchewan Health Authority (Anderson), Population Health, Saskatoon, Sask.; Department of Molecular Genetics (Awadalla), University of Toronto; Department of Computational Biology (Awadalla), Ontario Institute for Cancer Research; Centre for Global Health Research (Brown), Unity Health Toronto and University of Toronto, Toronto, Ont.; Public Health Laboratory (Charlton, Hinshaw, Tipples), Alberta Precision Laboratories, University of Alberta Hospital; Department of Laboratory Medicine and Pathology (Charlton, Tipples), and Li Ka Shing Institute of Virology, University of Alberta, Edmonton, Alta.; Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital (Colwill, Gingras), Sinai Health System, Toronto, Ont.; Canadian Blood Services (Drews); Department of Laboratory Medicine and Pathology (O'Brien, Pambrun, Drews), University of Alberta, Edmonton, Alta.; Department of Molecular Genetics (Gingras, Skead), University of Toronto; Centre for Global Health Research (Jha), Unity Health Toronto and University of Toronto, Toronto, Ont.; Public Health Laboratory (Kanji), Alberta Precision Laboratories, Foothills Medical Centre, and Section of Medical Microbiology (Kanji), Department of Pathology and Laboratory Medicine, and Division of Infectious Diseases, Department of Medicine, University of Calgary, Calgary, Alta.; Ontario Health Study (Kirsh, Skead), Ontario Institute for Cancer Research; Department of Molecular Genetics (Kirsh, Skead), and Dalla Lana School of Public Health (Kirsh), University of Toronto, Toronto, Ont.; Roy Romanow Provincial Lab (Lang), Saskatchewan Health Authority; College of Medicine (Lang), University of Saskatchewan, Saskatoon, Sask.; Department of Biochemistry, Microbiology and Immunology (Langlois), and Centre for Infection, Immunity and Inflammation (Langlois), University of Ottawa, Ottawa, Ont.; Division of Infectious Diseases-Regina (Lee), University of Saskatchewan; Saskatchewan Health Authority (Lee), Saskatoon, Sask.; Medical Affair and Innovation (Lewin), Héma-Québec, Montréal, Que.; Departments of Epidemiology and Community Medicine (O'Brien), and Pathology and Laboratory Medicine (Pambrun), Faculty of Medicine, University of Ottawa, Ottawa, Ont.; Department of Mathematics & Statistics (Stephens), McGill University, Montréal, Que.; Department of Medical Microbiology (Stein, Van Caeseele), University of Manitoba, and Cadham Provincial Laboratory, Winnipeg, Man.; School of Population and Global Health (Evans), McGill University; The Research Institute of the McGill University Health Centre (Mazer, Buckeridge), Montréal, Que.
出版信息
CMAJ. 2023 Aug 14;195(31):E1030-E1037. doi: 10.1503/cmaj.230249.
BACKGROUND
During the first year of the COVID-19 pandemic, the proportion of reported cases of COVID-19 among Canadians was under 6%. Although high vaccine coverage was achieved in Canada by fall 2021, the Omicron variant caused unprecedented numbers of infections, overwhelming testing capacity and making it difficult to quantify the trajectory of population immunity.
METHODS
Using a time-series approach and data from more than 900 000 samples collected by 7 research studies collaborating with the COVID-19 Immunity Task Force (CITF), we estimated trends in SARS-CoV-2 seroprevalence owing to infection and vaccination for the Canadian population over 3 intervals: prevaccination (March to November 2020), vaccine roll-out (December 2020 to November 2021), and the arrival of the Omicron variant (December 2021 to March 2023). We also estimated seroprevalence by geographical region and age.
RESULTS
By November 2021, 9.0% (95% credible interval [CrI] 7.3%-11%) of people in Canada had humoral immunity to SARS-CoV-2 from an infection. Seroprevalence increased rapidly after the arrival of the Omicron variant - by Mar. 15, 2023, 76% (95% CrI 74%-79%) of the population had detectable antibodies from infections. The rapid rise in infection-induced antibodies occurred across Canada and was most pronounced in younger age groups and in the Western provinces: Manitoba, Saskatchewan, Alberta and British Columbia.
INTERPRETATION
Data up to March 2023 indicate that most people in Canada had acquired antibodies against SARS-CoV-2 through natural infection and vaccination. However, given variations in population seropositivity by age and geography, the potential for waning antibody levels, and new variants that may escape immunity, public health policy and clinical decisions should be tailored to local patterns of population immunity.
背景
在 COVID-19 大流行的第一年，加拿大报告的 COVID-19 病例比例低于 6%。尽管到 2021 年秋季加拿大已实现高疫苗接种覆盖率，但奥密克戎变异株导致感染人数前所未有，检测能力不堪重负，使得量化人群免疫力轨迹变得困难。
方法
我们使用时间序列方法和由 7 项研究与 COVID-19 免疫工作组（CITF）合作收集的超过 90 万份样本数据，估算了加拿大人群因感染和接种疫苗而导致的 SARS-CoV-2 血清阳性率趋势，跨越 3 个时间段：疫苗接种前（2020 年 3 月至 11 月）、疫苗推出（2020 年 12 月至 2021 年 11 月）和奥密克戎变异株到来（2021 年 12 月至 2023 年 3 月）。我们还按地理位置和年龄估计了血清阳性率。
结果
到 2021 年 11 月，加拿大 9.0%（95%置信区间[CrI]7.3%-11%）的人因感染产生针对 SARS-CoV-2 的体液免疫。奥密克戎变异株出现后，血清阳性率迅速上升 - 到 2023 年 3 月 15 日，76%（95% CrI 74%-79%）的人口因感染产生可检测抗体。感染诱导抗体的快速上升发生在加拿大各地，在年轻年龄组和西部省份（曼尼托巴省、萨斯喀彻温省、艾伯塔省和不列颠哥伦比亚省）最为明显。
解释
截至 2023 年 3 月的数据表明，加拿大大多数人通过自然感染和接种疫苗获得了针对 SARS-CoV-2 的抗体。然而，鉴于年龄和地理位置的人口血清阳性率存在差异、抗体水平可能下降以及可能逃避免疫的新变异株，公共卫生政策和临床决策应根据当地人群免疫模式进行调整。
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