Center for Precision Environmental Health, Department of Medicine, Section of Epidemiology and Population Sciences, Baylor College of Medicine, Houston, Texas, USA.
Department of Statistics, Rice University, Houston, Texas, USA.
J Infect Dis. 2021 Nov 22;224(10):1649-1657. doi: 10.1093/infdis/jiab203.
In contrast to studies that relied on volunteers or convenience sampling, there are few population-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence investigations and most were conducted early in the pandemic. The health department of the fourth largest US city recognized that sound estimates of viral impact were needed to inform decision making.
Adapting standardized disaster research methodology, in September 2020 the city was divided into high and low strata based on reverse-transcriptase polymerase chain reaction (RT-PCR) positivity rates; census block groups within each stratum were randomly selected with probability proportional to size, followed by random selection of households within each group. Using 2 immunoassays, the proportion of infected individuals was estimated for the city, by positivity rate and sociodemographic and other characteristics. The degree of underascertainment of seroprevalence was estimated based on RT-PCR-positive cases.
Seroprevalence was estimated to be 14% with near 2-fold difference in areas with high (18%) versus low (10%) RT-PCR positivity rates and was 4 times higher compared to case-based surveillance data.
Seroprevalence was higher than previously reported and greater than estimated from RT-PCR data. Results will be used to inform public health decisions about testing, outreach, and vaccine rollout.
与依赖志愿者或便利抽样的研究相比，很少有基于人群的严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）血清流行率调查，而且大多数调查都是在大流行早期进行的。美国第四大城市的卫生部门认识到，需要对病毒的影响进行准确的估计，以便为决策提供信息。
2020 年 9 月，该市根据逆转录酶聚合酶链反应（RT-PCR）阳性率将适应标准化灾害研究方法分为高和低两层；在每一层内，按大小与概率成比例随机选择普查街区组，然后在每组内随机选择家庭。使用 2 种免疫分析法，根据阳性率以及社会人口学和其他特征，估计城市的感染个体比例。根据 RT-PCR 阳性病例估计血清流行率的低估程度。
血清流行率估计为 14%，高（18%）与低（10%）RT-PCR 阳性率地区的差异接近 2 倍，与基于病例的监测数据相比高出 4 倍。
血清流行率高于先前报告的水平，也高于从 RT-PCR 数据估计的水平。结果将用于告知有关检测、外展和疫苗推出的公共卫生决策。
