Background

Given the importance of neutralising antibodies in protection against SARS-CoV-2 infection, it is critical to assess neutralisation persistence long-term following recovery. This study investigated neutralisation titres against SARS-CoV-2 up to 6 months post-symptom onset in individuals with mild COVID-19.

Methods

Plasma neutralisation titres in convalescent COVID-19 individuals were determined at baseline and 6 months post-symptom onset using a cell culture infectious SARS-CoV-2 assay. Total SARS-CoV-2 spike-specific IgG and IgA binding was measured using a lectin capture ELISA and compared between timepoints and correlated to neutralising titres.

Findings

All 48 convalescent COVID-19 individuals were found to have detectable SARS-CoV-2 50% inhibitory dilution neutralisation titres (ID₅₀) at baseline and 6 months post-symptom onset with mean ID₅₀ of 1/943 and 1/411, respectively. SARS-CoV-2 neutralisation titres peaked within 1-2 months post-symptom onset. However, 50% of individuals showed comparable ID₅₀ at baseline and 6 months post-symptom onset. Both SARS-CoV-2 spike-specific IgG and IgA levels correlated well with neutralising titres. IgG binding was found to be sustained up to 6 months post-symptom onset, whereas IgA levels declined.

Interpretation

This study demonstrates durability of SARS-CoV-2 spike-specific IgG and neutralisation responses following recovery from mild COVID-19. Thus, all subjects included in this study might potentially have protective levels of neutralising antibodies 6 months post-symptom onset. This study also demonstrates a relationship between spike-specific IgA and neutralisation decline, with implications for long-term protection against SARS-CoV-2 infection.

Funding

Novo Nordisk Foundation, Independent Research Fund Denmark and Danish Agency for Science and Higher Education.

中文翻译：

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对 SARS-CoV-2 的中和滴度在轻度 COVID-19 个体出现症状后 6 个月内持续

背景

鉴于中和抗体在预防 SARS-CoV-2 感染方面的重要性，评估恢复后的长期中和持续性至关重要。本研究调查了轻度 COVID-19 患者在症状出现后长达 6 个月内针对 SARS-CoV-2 的中和滴度。

方法

使用细胞培养感染性 SARS-CoV-2 测定法在基线和症状发作后 6 个月确定了康复期 COVID-19 个体的血浆中和滴度。使用凝集素捕获 ELISA 测量总 SARS-CoV-2 尖峰特异性 IgG 和 IgA 结合，并在时间点之间进行比较并与中和滴度相关联。

发现

发现所有 48 名康复期 COVID-19 个体在基线和症状发作后 6 个月均具有可检测的 SARS-CoV-2 50% 抑制稀释中和滴度（ID ₅₀），平均 ID ₅₀分别为 1/943 和 1/411 . SARS-CoV-2 中和滴度在症状出现后 1-2 个月内达到峰值。然而，50% 的个体在基线和症状出现后 6 个月显示出可比的 ID ₅₀。SARS-CoV-2 尖峰特异性 IgG 和 IgA 水平均与中和滴度相关。IgG 结合被发现在症状出现后持续长达 6 个月，而 IgA 水平下降。

解释

这项研究证明了从轻度 COVID-19 中恢复后 SARS-CoV-2 尖峰特异性 IgG 和中和反应的持久性。因此，本研究中包括的所有受试者在症状出现后 6 个月可能具有保护水平的中和抗体。这项研究还证明了尖峰特异性 IgA 与中和作用下降之间的关系，这对长期预防 SARS-CoV-2 感染具有影响。

资金

诺和诺德基金会、丹麦独立研究基金和丹麦科学与高等教育机构。