Objective Synthesise evidence on production of SARS-CoV-2 antibodies in human milk of individuals who had COVID-19, and antibodies’ ability to neutralise SARS-CoV-2 infectivity. Design A systematic review of studies published from 1 December 2019 to 16 February 2021 without study design restrictions. Setting Data were sourced from PubMed, MEDLINE, Embase, CNKI, CINAHL and WHO COVID-19 database. Search was also performed through reviewing references of selected articles, Google Scholar and preprint servers. Studies that tested human milk for antibodies to SARS-CoV-2 were included. Patients Individuals with COVID-19 infection and human milk tested for anti-SARS-CoV-2 neutralising antibodies. Main outcome measures The presence of neutralising antibodies in milk samples provided by individuals with COVID-19 infection. Results Individual participant data from 161 persons (14 studies) were extracted and re-pooled. Milk from 133 (82.6%) individuals demonstrated the presence of anti-SARS-CoV-2 immunoglobulin A (IgA), IgM and/or IgG. Illness severity data were available in 146 individuals; 5 (3.4%) had severe disease, 128 (87.7%) had mild disease, while 13 (8.9%) were asymptomatic. Presence of neutralising antibodies in milk from 20 (41.7%) of 48 individuals neutralised SARS-CoV-2 infectivity in vitro. Neutralising capacity of antibodies was lost after Holder pasteurisation but preserved after high-pressure pasteurisation. Conclusion Human milk of lactating individuals after COVID-19 infection contains anti-SARS-CoV-2-specific IgG, IgM and/or IgA, even after mild or asymptomatic infection. Current evidence demonstrates that these antibodies can neutralise SARS-CoV-2 virus in vitro. Holder pasteurisation deactivates SARS-CoV-2-specific IgA, while high-pressure pasteurisation preserves the SARS-CoV-2-specific IgA function. All data relevant to the study are included in the article or uploaded as supplemental information. The data were extracted from the published literature. The details of all such literature used are included in the manuscript.

中文翻译：

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母乳中 SARS-CoV-2 特异性抗体的滴度和中和能力：系统评价

目的 综合有关 COVID-19 感染者母乳中 SARS-CoV-2 抗体产生以及抗体中和 SARS-CoV-2 感染性能力的证据。设计 对2019年12月1日至2021年2月16日发表的研究进行系统回顾，没有研究设计限制。设置数据来源于 PubMed、MEDLINE、Embase、CNKI、CINAHL 和 WHO COVID-19 数据库。搜索还通过审查选定文章的参考文献、谷歌学术搜索和预印本服务器进行。其中包括测试母乳中 SARS-CoV-2 抗体的研究。患者 感染了 COVID-19 并使用母乳检测抗 SARS-CoV-2 中和抗体的个体。主要结果指标 COVID-19 感染者提供的牛奶样本中是否存在中和抗体。结果 提取并重新汇总了 161 人（14 项研究）的个体参与者数据。133 名 (82.6%) 个体的牛奶中显示出抗 SARS-CoV-2 免疫球蛋白 A (IgA)、IgM 和/或 IgG 的存在。可获得 146 人的疾病严重程度数据；5人（3.4%）为重症，128人（87.7%）为轻症，13人（8.9%）为无症状。48 名个体中的 20 名（41.7%）的牛奶中存在中和抗体，在体外中和了 SARS-CoV-2 感染性。Holder 巴氏灭菌后抗体的中和能力丧失，但高压巴氏灭菌后保留。结论 COVID-19 感染后的哺乳期个体的母乳中含有抗 SARS-CoV-2 特异性 IgG、IgM 和/或 IgA，即使是轻度或无症状感染后也是如此。目前的证据表明这些抗体可以在体外中和 SARS-CoV-2 病毒。支架巴氏灭菌可灭活 SARS-CoV-2 特异性 IgA，而高压巴氏灭菌可保留 SARS-CoV-2 特异性 IgA 功能。与研究相关的所有数据都包含在文章中或作为补充信息上传。数据摘自已发表的文献。所有使用的此类文献的详细信息都包含在手稿中。