BACKGROUND In Canada's largest COVID-19 serological study, SARS-CoV-2 antibodies in blood donors have been monitored since 2020. No study has analysed changes in the association between anti-N seropositivity (a marker of recent infection) and geographic and sociodemographic characteristics over the pandemic. METHODS Using Bayesian multi-level models with spatial effects at the census division level, we analysed changes in correlates of SARS-CoV-2 anti-N seropositivity across three periods in which different variants predominated (pre-Delta, Delta and Omicron). We analysed disparities by geographic area, individual traits (age, sex, race) and neighbourhood factors (urbanicity, material deprivation and social deprivation). Data were from 420 319 blood donations across four regions (Ontario, British Columbia [BC], the Prairies and the Atlantic region) from December 2020 to November 2022. RESULTS Seropositivity was higher for racialized minorities, males and individuals in more materially deprived neighbourhoods in the pre-Delta and Delta waves. These subgroup differences dissipated in the Omicron wave as large swaths of the population became infected. Across all waves, seropositivity was higher in younger individuals and those with lower neighbourhood social deprivation. Rural residents had high seropositivity in the Prairies, but not other regions. Compared to generalized linear models, multi-level models with spatial effects had better fit and lower error when predicting SARS-CoV-2 anti-N seropositivity by geographic region. CONCLUSIONS Correlates of recent COVID-19 infection have evolved over the pandemic. Many disparities lessened during the Omicron wave, but public health intervention may be warranted to address persistently higher burden among young people and those with less social deprivation.

中文翻译：

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加拿大献血者中 COVID-19 血清阳性差异的时间趋势。


背景 在加拿大最大的 COVID-19 血清学研究中，自 2020 年以来一直在监测献血者的 SARS-CoV-2 抗体。没有研究分析抗 N 血清阳性（近期感染的标志）与地理和社会人口特征之间的关联变化超过大流行。方法 使用在人口普查分区层面具有空间效应的贝叶斯多层次模型，我们分析了不同变体占主导地位的三个时期（前 Delta、Delta 和 Omicron）中 SARS-CoV-2 抗 N 血清阳性相关性的变化。我们分析了地理区域、个人特征（年龄、性别、种族）和邻里因素（城市化、物质匮乏和社会匮乏）的差异。数据来自 2020 年 12 月至 2022 年 11 月期间四个地区（安大略省、不列颠哥伦比亚省 [BC]、大草原区和大西洋地区）的 420 319 次献血。 结果前 Delta 波和 Delta 波。随着大量人群被感染，这些亚组差异在 Omicron 浪潮中消失了。在所有浪潮中，年轻人和社区社会剥夺程度较低的人的血清阳性率较高。大草原地区农村居民的血清阳性率较高，但其他地区则不然。与广义线性模型相比，具有空间效应的多层次模型在按地理区域预测 SARS-CoV-2 抗 N 血清阳性时具有更好的拟合度和更低的误差。结论 近期 COVID-19 感染的相关性在大流行期间发生了变化。 在 Omicron 浪潮期间，许多差距有所缩小，但公共卫生干预可能是必要的，以解决年轻人和社会剥夺较少的人持续较高的负担。