Objective To evaluate pertussis antibody status of pregnant women and their newborns, and the impact of antenatal immunisation. Design Observational study. Setting Hospitals in urban western India. Participants Pregnant women and their newborns. Methods Pertussis antibody titres in mothers and their newborns were determined. Vaccinated and unvaccinated mothers and their newborns were compared for baseline characteristics, geometric mean titres (GMTs) and placental transfer ratio of antibodies. Multivariate logistic regression was performed to understand the influence of different factors on protective antibody titres. Results Of 284 mother–infant pairs, 75 mothers and 73 of their newborns were seropositive for anti-pertussis toxin (PT) IgG antibodies. 94 women were vaccinated in pregnancy; 51 (54.3%) of these mothers and newborns were PT IgG positive, compared with 24 (12.3%) of the women (and 22 newborns) not vaccinated in pregnancy. Women vaccinated in pregnancy and their newborns had higher GMT (30.88 and 32.54 IU/mL), compared with women who were not vaccinated (12.63%, 2.24 IU/mL) and their newborns (11.58%, 2.53 IU/mL). Placental transfer ratios in newborns of mothers vaccinated in pregnancy and those who had childhood immunisation or natural immunity were similar (1.05 and 1.12, respectively). Protective titres of antibodies at birth (>20 IU/mL) were observed in 72.3% vs 21% of newborns of vaccinated and unvaccinated pregnant women, respectively; influenced by mother’s vaccination status and seropositivity. Conclusion Protection against pertussis is low in newborns of mothers who are only immunised during childhood. Vaccination early in pregnancy boosts maternal and neonatal immunity. Data are available upon reasonable request. Data are available from the corresponding author upon reasonable request.

中文翻译：

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印度母婴对的百日咳血清阳性率：母婴免疫的作用

目的评价孕妇及其新生儿百日咳抗体状况及产前免疫的影响。设计观察研究。在印度西部城市设置医院。参与者 孕妇及其新生儿。方法测定母婴百日咳抗体滴度。比较接种疫苗和未接种疫苗的母亲及其新生儿的基线特征、几何平均滴度 (GMT) 和抗体的胎盘转移率。进行多变量逻辑回归以了解不同因素对保护性抗体滴度的影响。结果 在 284 对母婴中，75 名母亲和 73 名新生儿的抗百日咳毒素 (PT) IgG 抗体呈血清阳性。94 名妇女在怀孕期间接种了疫苗；51（54。这些母亲和新生儿中有 3%) 为 PT IgG 阳性，而在怀孕期间未接种疫苗的妇女（和 22 名新生儿）中有 24 名（12.3%）为阳性。与未接种疫苗的女性（12.63%，2.24 IU/mL）及其新生儿（11.58%，2.53 IU/mL）相比，孕期接种疫苗的女性及其新生儿的 GMT 较高（30.88 和 32.54 IU/mL）。孕期接种疫苗的母亲和接受过儿童免疫接种或自然免疫的母亲的新生儿胎盘移植率相似（分别为 1.05 和 1.12）。在接种疫苗和未接种疫苗的孕妇的新生儿中分别观察到 72.3% 和 21% 的出生时抗体保护滴度（>20 IU/mL）；受母亲的疫苗接种状况和血清阳性率的影响。结论 仅在儿童期接种疫苗的母亲的新生儿对百日咳的保护作用较低。妊娠早期接种疫苗可提高母婴免疫力。可根据合理要求提供数据。可根据合理要求从通讯作者处获得数据。