Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA.
JCI Insight. 2022 Apr 22;7(8):e157963. doi: 10.1172/jci.insight.157963.
BackgroundSARS-CoV-2 infections are frequently milder in children than adults, suggesting that immune responses may vary with age. However, information is limited regarding SARS-CoV-2 immune responses in young children.MethodsWe compared receptor binding domain-binding antibody (RBDAb) titers and SARS-CoV-2-neutralizing antibody titers, measured by pseudovirus-neutralizing antibody assay in serum specimens obtained from children aged 0-4 years and 5-17 years and in adults aged 18-62 years at the time of enrollment in a prospective longitudinal household study of SARS-CoV-2 infection.ResultsAmong 56 seropositive participants at enrollment, children aged 0-4 years had more than 10-fold higher RBDAb titers than adults (416 vs. 31, P < 0.0001) and the highest RBDAb titers in 11 of 12 households with seropositive children and adults. Children aged 0-4 years had only 2-fold higher neutralizing antibody than adults, resulting in higher binding-to-neutralizing antibody ratios compared with adults (2.36 vs. 0.35 for ID50, P = 0.0004).ConclusionThese findings suggest that young children mount robust antibody responses to SARS-CoV-2 following community infections. Additionally, these results support using neutralizing antibody to measure the immunogenicity of COVID-19 vaccines in children aged 0-4 years.FundingCDC (award 75D30120C08737).
SARS-CoV-2 感染在儿童中的症状通常比成人轻，这表明免疫反应可能因年龄而异。然而，关于儿童中 SARS-CoV-2 免疫反应的信息有限。
我们比较了在一项前瞻性纵向家庭 SARS-CoV-2 感染研究中，于招募时采集的 0-4 岁和 5-17 岁儿童以及 18-62 岁成人血清标本中的受体结合域结合抗体（RBDAb）滴度和 SARS-CoV-2 中和抗体滴度，该滴度通过假病毒中和抗体测定法测量。
在招募时的 56 名血清阳性参与者中，0-4 岁儿童的 RBDAb 滴度比成人高 10 多倍（416 比 31，P<0.0001），并且在 12 个血清阳性儿童和成人家庭中有 11 个家庭中 RBDAb 滴度最高。0-4 岁儿童的中和抗体仅比成人高 2 倍，与成人相比，其结合抗体与中和抗体的比值更高（ID50 为 2.36 比 0.35，P=0.0004）。
这些发现表明，在社区感染后，年幼的儿童会对 SARS-CoV-2 产生强烈的抗体反应。此外，这些结果支持在 0-4 岁儿童中使用中和抗体来衡量 COVID-19 疫苗的免疫原性。
美国 CDC（授予 75D30120C08737）。
