Maternal results.

Background
Data on SARS-CoV-2 infection in pregnancy and infancy has accumulated throughout the course of the pandemic, though evidence regarding asymptomatic SARS-CoV-2 infection and adverse birth outcomes are scarce. Limited information is available from countries in sub-Saharan Africa (SSA). The pregnant woman and infant COVID in Africa study (PeriCOVID Africa) is a South-South-North partnership involving hospitals and health centres in five countries: Malawi, Uganda, Mozambique, The Gambia, and Kenya. The study leveraged data from three ongoing prospective cohort studies: Preparing for Group B Streptococcal Vaccines (GBS PREPARE), SARS-CoV-2 infection and COVID-19 in women and their infants in Kampala and Mukono (COMAC) and Pregnancy Care Integrating Translational Science Everywhere (PRECISE). In this paper we describe the seroepidemiology of SARS-CoV-2 infection in pregnant women enrolled in sites in Uganda and Malawi, and the impact of SARS-CoV-2 infection on pregnancy and infant outcomes.
Outcome
Seroprevalence of SARS-CoV-2 antibodies in maternal blood, reported as the proportion of seropositive women by study site and wave of COVID-19 within each country.
Methods
The PeriCOVID study was a prospective mother-infant cohort study that recruited pregnant women at any gestation antenatally or on the day of delivery. Maternal and cord blood samples were tested for SARS-CoV-2 antibodies using Wantai and Euroimmune ELISA. In periCOVID Uganda and Malawi nose and throat swabs for SARS-Cov-2 RT-PCR were obtained.
Results
In total, 1379 women were enrolled, giving birth to 1387 infants. Overall, 63% of pregnant women had a SARS-CoV-2 positive serology. Over subsequent waves (delta and omicron), in the absence of vaccination, seropositivity rose from 20% to over 80%. The placental transfer GMR was 1.7, indicating active placental transfer of anti-spike IgG. There was no association between SARS-CoV-2 antibody positivity and adverse pregnancy or infancy outcomes.

研究背景
新冠病毒（SARS-CoV-2）在妊娠及婴儿期感染的相关数据，在新冠大流行期间已逐步积累，但针对无症状新冠病毒感染与不良妊娠结局的相关证据仍较为匮乏。撒哈拉以南非洲（sub-Saharan Africa, SSA）地区的相关信息尤为有限。非洲孕产妇与婴儿新冠研究（PeriCOVID Africa）是一项南南北合作项目，覆盖马拉维、乌干达、莫桑比克、冈比亚和肯尼亚五个国家的医院与医疗中心。本研究整合了三项正在进行的前瞻性队列研究的数据：B族链球菌疫苗研发准备项目（GBS PREPARE）、坎帕拉与穆科科地区孕产妇及其婴儿的新冠病毒感染与新冠病情研究（COMAC），以及全球转化科学整合妊娠护理项目（PRECISE）。本文旨在描述乌干达与马拉维各研究点入组孕产妇的新冠病毒感染血清流行病学特征，以及新冠病毒感染对妊娠与婴儿结局的影响。

研究结局
孕产妇血液中新冠病毒抗体的血清阳性率，以各研究点及各国内新冠疫情浪潮下的血清阳性女性占比进行报告。

研究方法
PeriCOVID研究为一项前瞻性母婴队列研究，在产前任意孕周或分娩当日招募孕产妇。采用万泰（Wantai）与欧蒙（Euroimmune）ELISA试剂盒检测孕产妇及脐带血样本中的新冠病毒抗体。在乌干达与马拉维的PeriCOVID研究点中，还采集了鼻咽拭子样本用于新冠病毒RT-PCR检测。

研究结果
本研究共纳入1379名孕产妇，分娩1387名婴儿。总体而言，63%的孕产妇新冠病毒血清学检测结果为阳性。在后续的德尔塔（Delta）与奥密克戎（Omicron）疫情浪潮期间，在未开展疫苗接种的情况下，血清阳性率从20%升至80%以上。胎盘转移几何平均比率（GMR）为1.7，提示抗刺突IgG抗体可通过胎盘进行主动转运。未发现新冠病毒抗体阳性与不良妊娠结局或婴儿不良结局存在关联。