Aglipay Mary, Kwong Jeffrey C, Colwill Karen, Gringas Anne-Claude, Tuite Ashleigh, Mamdani Muhammad, Keown-Stoneman Charles, Birken Catherine, Maguire Jonathon
Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada.
Can J Public Health. 2024 Dec;115(6):913-923. doi: 10.17269/s41997-024-00916-3. Epub 2024 Aug 21.
Characterizing the seroprevalence of SARS-CoV-2 antibodies in children is needed to optimize the COVID-19 public health response. We quantified the seroprevalence of SARS-CoV-2 infection-acquired antibodies and vaccine-acquired antibodies among children receiving primary care in Toronto, Canada.
We conducted a longitudinal cohort study between January 2021 and November 2022 in healthy children aged 0-16 years receiving primary care in Toronto. The primary and secondary outcomes were seroprevalence of SARS-COV-2 infection-acquired antibodies and vaccine-acquired antibodies ascertained from finger-prick dried blood spots. Samples were tested using an enzyme-linked immunosorbent assay for antibodies to full-length spike trimer and nucleocapsid. We explored sociodemographic differences with Firth's penalized generalized estimating equations.
Of the 475 participants, 50.1% were girls and mean age was 6.4 years (SD = 3.2). We identified 103 children seropositive for infection-acquired antibodies, with a crude seroprevalence that rose from 2.6% (95%CI 1.39-4.92) from January to July 2021 to 50.7% (95%CI 39.5-61.8) by July to November 2022. Seroprevalence of vaccine-acquired antibodies was 45.2% by July to November 2022 (95%CI 34.3-56.58). No differences in sociodemographic factors (age, sex, income, or ethnicity) were identified for infection-acquired antibodies; however, children with vaccine-acquired antibodies were more likely to be older, have mothers with university education, and have mothers who had also been vaccinated.
Our results provide a benchmark for seroprevalence of SARS-CoV-2 antibodies in children in Toronto. Ongoing monitoring of the serological status of children is important, particularly with the emergence of new variants of concern, low vaccine coverage, and discontinuation of PCR testing.
为优化新冠疫情公共卫生应对措施，有必要了解儿童中新冠病毒2型（SARS-CoV-2）抗体的血清流行率。我们对加拿大多伦多接受初级保健的儿童中SARS-CoV-2感染获得性抗体和疫苗获得性抗体的血清流行率进行了量化。
我们在2021年1月至2022年11月期间对多伦多0至16岁接受初级保健的健康儿童进行了一项纵向队列研究。主要和次要结局是通过手指刺血干血斑确定的SARS-CoV-2感染获得性抗体和疫苗获得性抗体的血清流行率。使用酶联免疫吸附测定法检测样本中针对全长刺突三聚体和核衣壳的抗体。我们使用Firth惩罚广义估计方程探讨了社会人口统计学差异。
在475名参与者中，50.1%为女孩，平均年龄为6.4岁（标准差=3.2）。我们确定了103名感染获得性抗体血清阳性的儿童，其粗血清流行率从2021年1月至7月的2.6%（95%置信区间1.39-4.92）上升至2022年7月至11月的50.7%（95%置信区间39.5-61.8）。2022年7月至11月疫苗获得性抗体的血清流行率为45.2%（95%置信区间34.3-56.58）。在感染获得性抗体方面，未发现社会人口统计学因素（年龄、性别、收入或种族）存在差异；然而，有疫苗获得性抗体的儿童更有可能年龄较大，母亲具有大学学历，且母亲也接种过疫苗。
我们的结果为多伦多儿童中SARS-CoV-2抗体的血清流行率提供了一个基准。持续监测儿童的血清学状态很重要，特别是在出现新的关注变异株、疫苗接种覆盖率低以及停止PCR检测的情况下。
