Abstract：
We estimated monthly cross-sectional seroprevalence rates of anti-nucleocapsid (anti-N) and anti-spike (anti-S) antibodies to severe acute respiratory syndrome coronavirus 2 in two U.S. nationwide studies. The nationwide blood donor seroprevalence (NBDS) study included specimens from blood donors, while the nationwide commercial laboratory seroprevalence (NCLS) study included residual serum specimens tested in commercial laboratories for reasons unrelated to the assessment of coronavirus disease 2019 infection. In September-December 2021, specimens collected from both nationwide studies were tested for anti-N antibodies. In September-October 2021, specimens from both studies within a five-state area were tested for anti-S antibodies. We used raking methods to adjust all seroprevalence estimates by the population distribution of key demographics in included states. Seroprevalence estimates of each antibody type were compared across the two studies for specimens drawn in the same U.S. states during the same time period. Our analysis revealed that over a 4-month period, national NCLS monthly anti-N estimates were 0.5-1.9 percentage points higher than NBDS estimates. In contrast, across five states during a 2-month period, NBDS anti-S estimates were 7.6 and 8.2 percentage points higher than NCLS estimates. The observed differences in seroprevalence estimates between the NBDS and NCLS studies may be attributed to variations in the characteristics of the study sample populations, particularly with respect to health status, health behaviors, and vaccination status. These differences should be considered in the interpretation of seroprevalence study results based on blood donors or commercial lab residual specimens.
OBJECTIVE: This study was the first systematic comparison between two nationwide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) studies which estimated seroprevalence, or the proportion of the population with antibodies to the virus, using differing convenience sample populations. One study tested blood donor specimens; the other study tested specimens left over from clinical blood tests. The seroprevalence of anti-nucleocapsid and anti-spike antibodies was compared in the same states during the same months with statistical adjustments based on state demographics. Similar anti-nucleocapsid antibody seroprevalence estimates produced by two independent studies using differing convenience samples build confidence in the generalizability of their anti-nucleocapsid findings. Due to high blood donor vaccine rates, blood donor SARS-CoV-2 anti-spike antibody estimates might overestimate general population seroprevalence, an important consideration for interpreting national seroprevalence study results. Furthermore, because laboratory residuals and blood donations are two common sources of specimens for seroprevalence studies, study findings may be informative for other respiratory virus seroepidemiology studies.
OBJECTIVE: This study was the first systematic comparison between two nationwide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) studies which estimated seroprevalence, or the proportion of the population with antibodies to the virus, using differing convenience sample populations. One study tested blood donor specimens; the other study tested specimens left over from clinical blood tests. The seroprevalence of anti-nucleocapsid and anti-spike antibodies was compared in the same states during the same months with statistical adjustments based on state demographics. Similar anti-nucleocapsid antibody seroprevalence estimates produced by two independent studies using differing convenience samples build confidence in the generalizability of their anti-nucleocapsid findings. Due to high blood donor vaccine rates, blood donor SARS-CoV-2 anti-spike antibody estimates might overestimate general population seroprevalence, an important consideration for interpreting national seroprevalence study results. Furthermore, because laboratory residuals and blood donations are two common sources of specimens for seroprevalence studies, study findings may be informative for other respiratory virus seroepidemiology studies.
摘要：
在美国两项全国性研究中，我们估计了抗严重急性呼吸综合征冠状病毒2的抗核衣壳（抗N）和抗刺突（抗S）抗体的每月横截面血清阳性率。全国献血者血清阳性率（NBDS）研究包括来自献血者的标本，而全国商业实验室血清阳性率（NCLS）研究包括在商业实验室检测的残留血清标本，其原因与2019年冠状病毒病感染评估无关。在2021年9月至12月，从两项全国性研究中收集的标本都进行了抗N抗体测试。在2021年9月至10月，对来自五州地区的两项研究的标本进行了抗S抗体测试。我们使用raking方法根据所包括州关键人口统计学的人口分布来调整所有血清阳性率估计。在两项研究中，比较了在同一时期在美国同一州抽取的标本的每种抗体类型的血清阳性率估计值。我们的分析显示，在4个月的时间里，全国NCLS月度反N估计值比NBDS估计值高0.5-1.9个百分点。相比之下,在两个月的时间里，五个州，NBDS抗S估计比NCLS估计高7.6和8.2个百分点。观察到的NBDS和NCLS研究之间血清阳性率估计的差异可能归因于研究样本群体特征的变化，特别是在健康状况方面，健康行为,和疫苗接种状况。在基于献血者或商业实验室残留标本的血清阳性率研究结果的解释中，应考虑这些差异。
目的：这项研究是两项全国性的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）研究之间的首次系统比较，这些研究估计了血清阳性率，或者有病毒抗体的人口比例，使用不同的便利样本群体。一项研究测试了献血者标本；另一项研究测试了临床血液检查留下的标本。在相同月份的相同状态下，比较了抗核衣壳和抗刺突抗体的血清阳性率，并根据状态人口统计进行了统计调整。两个独立研究使用不同的便利样本产生的类似的抗核衣壳抗体血清阳性率估计建立了对其抗核衣壳发现的普遍性的信心。由于献血者的疫苗接种率高,献血者SARS-CoV-2抗尖峰抗体估计可能会高估一般人群血清阳性率，解释国家血清阳性率研究结果的重要考虑因素。此外，因为实验室残留物和献血是血清阳性率研究的两种常见样本来源，研究结果可能为其他呼吸道病毒血清流行病学研究提供参考。
目的：这项研究是两项全国性的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）研究之间的首次系统比较，这些研究估计了血清阳性率，或者有病毒抗体的人口比例，使用不同的便利样本群体。一项研究测试了献血者标本；另一项研究测试了临床血液检查留下的标本。在相同月份的相同状态下，比较了抗核衣壳和抗刺突抗体的血清阳性率，并根据状态人口统计进行了统计调整。两个独立研究使用不同的便利样本产生的类似的抗核衣壳抗体血清阳性率估计建立了对其抗核衣壳发现的普遍性的信心。由于献血者的疫苗接种率高,献血者SARS-CoV-2抗尖峰抗体估计可能会高估一般人群血清阳性率，解释国家血清阳性率研究结果的重要考虑因素。此外，因为实验室残留物和献血是血清阳性率研究的两种常见样本来源，研究结果可能为其他呼吸道病毒血清流行病学研究提供参考。
