IMPORTANCE BNT162b2 messenger RNA (mRNA) COVID-19 vaccination in the third trimester was found to be associated with a strong maternal humoral IgG response that crossed the placenta and approached maternal titers in the newborn. OBJECTIVE To evaluate maternal and neonatal SARS-CoV-2 immunoglobulin G (IgG) antibody levels at birth after mRNA COVID-19 vaccination during the second trimester of pregnancy. DESIGN, SETTING, AND PARTICIPANTS This prospective cohort study, conducted at a single medical center in Haifa, Israel, from May to July 2021, included women with a singleton pregnancy over 24 weeks of gestation at least 7 days after receipt of their second COVID-19 vaccine dose who were not known to be previously infected with COVID-19. EXPOSURES BNT162b2 (Pfizer/BioNTech) vaccination. MAIN OUTCOMES AND MEASURES The primary outcomes were SARS-CoV-2 IgG antibody titers measured in the parturient at admission and in the umbilical cord blood within 30 minutes after delivery. Secondary outcomes were the correlation between antibody titers, feto-maternal characteristics, maternal adverse effects after vaccination, and time interval from vaccination to delivery. RESULTS Antibody levels were measured for 129 women (mean [SD] age, 31.9 [4.9] years) and 114 neonates, with 100% of the tests having positive results. The mean (SD) gestational age at administration of the second vaccine dose was 24.9 (3.3) weeks. Neonatal IgG titers were 2.6 times higher than maternal titers (median [range], 3315.7 [350.1-17 643.5] AU/mL vs 1185.2 [146.6-32 415.1] AU/mL). A positive correlation was demonstrated between maternal and neonatal antibodies (r = 0.92; 95% CI, 0.89-0.94). Multivariable analysis revealed that for each week that passed since receipt of the second vaccine dose, maternal and neonatal antibody levels changed by -10.9% (95% CI, -17.2% to -4.2%; P = .002) and -11.7% (95% CI, -19.0 to -3.8%; P = .005), respectively. For each 1-year increase in the mother's age, maternal and neonatal antibody levels changed by -3.1% (95% CI, -5.3% to -0.9%; P = .007) and -2.7% (95% CI, -5.2% to -0.1%; P = .04), respectively. CONCLUSIONS AND RELEVANCE In this cohort study, receipt of the BNT162b2 mRNA COVID-19 vaccine during the second trimester of pregnancy was associated with maternal and neonatal humoral responses, as reflected in maternal and neonatal SARS-CoV-2 IgG antibody levels measured after delivery. These findings support COVID-19 vaccination of pregnant individuals during the second trimester to achieve maternal protection and newborn safety during the pandemic.

中文翻译：

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在妊娠中期收到 BNT162b2 信使 RNA COVID-19 疫苗后分娩时的母婴 SARS-CoV-2 免疫球蛋白 G 抗体水平。

重要性 BNT162b2 信使 RNA (mRNA) COVID-19 在妊娠晚期接种疫苗被发现与强烈的母体体液 IgG 反应相关，该反应穿过胎盘并接近新生儿的母体滴度。目的 评估妊娠中期 mRNA COVID-19 疫苗接种后出生时母婴 SARS-CoV-2 免疫球蛋白 G (IgG) 抗体水平。设计、地点和参与者 这项前瞻性队列研究于 2021 年 5 月至 2021 年 7 月在以色列海法的一家医疗中心进行，纳入了妊娠超过 24 周且在收到第二次 COVID- 19 剂接种疫苗的人以前不知道是否感染过 COVID-19。暴露 BNT162b2 (Pfizer/BioNTech) 疫苗接种。主要结果和测量 主要结果是在入院时和分娩后 30 分钟内在脐带血中测量的 SARS-CoV-2 IgG 抗体滴度。次要结果是抗体滴度、胎儿-母体特征、疫苗接种后母体不良反应以及从疫苗接种到分娩的时间间隔之间的相关性。结果 对 129 名妇女（平均 [SD] 年龄，31.9 [4.9] 岁）和 114 名新生儿的抗体水平进行了测量，100% 的测试结果呈阳性。接种第二剂疫苗时的平均 (SD) 胎龄为 24.9 (3.3) 周。新生儿 IgG 滴度比母体滴度高 2.6 倍（中位数 [范围]，3315.7 [350.1-17 643.5] AU/mL 对比 1185.2 [146.6-32 415.1] AU/mL）。母体抗体和新生儿抗体呈正相关（r = 0.92；95% CI，0.89-0.94）。多变量分析显示，自接种第二剂疫苗后每周，母体和新生儿抗体水平变化 -10.9%（95% CI，-17.2% 至 -4.2%；P = .002）和 -11.7%（ 95% CI，-19.0 至 -3.8%；P = .005）。母亲年龄每增加 1 年，母体和新生儿抗体水平就会变化 -3.1%（95% CI，-5.3% 至 -0.9%；P = .007）和 -2.7%（95% CI，-5.2 % 至 -0.1%；P = .04）。结论和相关性在这项队列研究中，在妊娠中期接种 BNT162b2 mRNA COVID-19 疫苗与母体和新生儿的体液反应相关，这反映在分娩后测量的母体和新生儿 SARS-CoV-2 IgG 抗体水平上。