National Centre for Immunisation Research and Surveillance, Westmead, NSW, Australia.
Faculty of Medicine and Health, University of Sydney's Hospital Westmead Clinical School, Westmead, NSW, Australia.
PLoS One. 2024 Sep 18;19(9):e0300555. doi: 10.1371/journal.pone.0300555. eCollection 2024.
Following reduction of public health and social measures concurrent with SARS-CoV-2 Omicron emergence in late 2021 in Australia, COVID-19 case notification rates rose rapidly. As rates of direct viral testing and reporting dropped, true infection rates were most likely to be underestimated.
To better understand infection rates and immunity in this population, we aimed to estimate SARS-CoV-2 seroprevalence in Australians aged 0-19 years.
We conducted a national cross sectional serosurvey from June 1, 2022, to August 31, 2022, in children aged 0-19 years undergoing an anesthetic procedure at eight tertiary pediatric hospitals. Participant questionnaires were administered, and blood samples tested using the Roche Elecsys Anti-SARS-CoV-2 total spike and nucleocapsid antibody assays. Spike and nucleocapsid seroprevalence adjusted for geographic and socioeconomic imbalances in the participant sample compared to the Australian population was estimated using multilevel regression and poststratification within a Bayesian framework.
Blood was collected from 2,046 participants (median age: 6.6 years). The overall adjusted seroprevalence of spike-antibody was 92.1% (95% credible interval (CrI) 91.0-93.3%) and nucleocapsid-antibody was 67.0% (95% CrI 64.6-69.3). In unvaccinated children spike and nucleocapsid antibody seroprevalences were 84.2% (95% CrI 81.9-86.5) and 67.1% (95%CrI 64.0-69.8), respectively. Seroprevalence was similar across geographic remoteness index and socioeconomic quintiles. Nucleocapsid antibody seroprevalence increased with age while the point seroprevalence of the spike antibody seroprevalence decreased in the first year of life and then increased to 97.8 (95% Crl 96.1-99.2) by 12-15 years of age.
Most Australian children and adolescents aged 0-19 years, across all jurisdictions were infected with SARS-CoV-2 by August 2022, suggesting rapid and uniform spread across the population in a very short time period. High seropositivity in unvaccinated children informed COVID-19 vaccine recommendations in Australia.
2021 年底，澳大利亚在 SARS-CoV-2 奥密克戎出现后，公共卫生和社会措施随之减少，COVID-19 病例报告率迅速上升。由于直接病毒检测和报告率下降，实际感染率很可能被低估。
为了更好地了解该人群的感染率和免疫力，我们旨在估计澳大利亚 0-19 岁人群中 SARS-CoV-2 的血清流行率。
我们于 2022 年 6 月 1 日至 2022 年 8 月 31 日在 8 家三级儿科医院进行了一项全国性的横断面血清学调查，对接受麻醉程序的 0-19 岁儿童进行调查。参与者填写问卷，并使用罗氏 Elecsys Anti-SARS-CoV-2 总刺突和核衣壳抗体检测试剂盒检测血液样本。使用多层回归和贝叶斯框架内的后分层，对参与者样本与澳大利亚人口的地理和社会经济不平衡进行调整，估计刺突和核衣壳抗体的血清流行率。
共采集 2046 名参与者的血液（中位年龄：6.6 岁）。总体调整后的刺突抗体血清流行率为 92.1%（95%可信区间[CrI] 91.0-93.3%），核衣壳抗体血清流行率为 67.0%（95%CrI 64.6-69.3%）。未接种疫苗的儿童中，刺突和核衣壳抗体的血清流行率分别为 84.2%（95% CrI 81.9-86.5%）和 67.1%（95%CrI 64.0-69.8%）。地理偏远指数和社会经济五分位数之间的血清流行率相似。核衣壳抗体血清流行率随年龄增长而增加，而刺突抗体血清流行率在生命的第一年呈下降趋势，然后在 12-15 岁时增加到 97.8%（95% Crl 96.1-99.2%）。
截至 2022 年 8 月，大多数澳大利亚 0-19 岁的儿童和青少年都感染了 SARS-CoV-2，这表明在很短的时间内，病毒在人群中迅速而均匀地传播。未接种疫苗的儿童中高血清阳性率为澳大利亚的 COVID-19 疫苗建议提供了信息。
