Department of Obstetrics and Fetal Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Front Immunol. 2021 Jun 3;12:698578. doi: 10.3389/fimmu.2021.698578. eCollection 2021.
Pregnant women have been carefully observed during the COVID-19 pandemic, as the pregnancy-specific immune adaptation is known to increase the risk for infections. Recent evidence indicates that even though most pregnant have a mild or asymptomatic course, a severe course of COVID-19 and a higher risk of progression to diseases have also been described, along with a heightened risk for pregnancy complications. Yet, vertical transmission of the virus is rare and the possibility of placental SARS-CoV-2 infection as a prerequisite for vertical transmission requires further studies. We here assessed the severity of COVID-19 and onset of neonatal infections in an observational study of women infected with SARS-CoV-2 during pregnancy. Our placental analyses showed a paucity of SARS-CoV-2 viral expression in term placentae under acute infection. No viral placental expression was detectable in convalescent pregnant women. Inoculation of placental explants generated from placentas of non-infected women at birth with SARS-CoV-2 revealed inefficient SARS-CoV-2 replication in different types of placental tissues, which provides a rationale for the low viral expression. We further detected specific SARS-CoV-2 T cell responses in pregnant women within a few days upon infection, which was undetectable in cord blood. Our present findings confirm that vertical transmission of SARS-CoV-2 is rare, likely due to the inefficient virus replication in placental tissues. Despite the predominantly benign course of infection in most mothers and negligible risk of vertical transmission, continuous vigilance on the consequences of COVID-19 during pregnancy is required, since the maternal immune activation in response to the SARS-CoV2 infection may have long-term consequences for children's health.
在 COVID-19 大流行期间，孕妇受到了仔细观察，因为众所周知，妊娠特异性免疫适应会增加感染的风险。最近的证据表明，尽管大多数孕妇的病程较轻或无症状，但也有描述表明 COVID-19 病情严重，疾病进展风险较高，并且妊娠并发症的风险增加。然而，病毒的垂直传播很少见，胎盘 SARS-CoV-2 感染作为垂直传播的先决条件需要进一步研究。我们在此评估了在一项对妊娠期间感染 SARS-CoV-2 的女性进行的观察性研究中 COVID-19 的严重程度和新生儿感染的发生情况。我们的胎盘分析表明，在急性感染下足月胎盘中的 SARS-CoV-2 病毒表达很少。在康复期孕妇中无法检测到病毒的胎盘表达。用 SARS-CoV-2 接种从出生时未感染妇女的胎盘中生成的胎盘外植体，揭示了不同类型胎盘组织中 SARS-CoV-2 的复制效率低下，这为低病毒表达提供了依据。我们还在感染后几天内在孕妇中检测到了特异性 SARS-CoV-2 T 细胞反应，而在脐血中则无法检测到。我们目前的研究结果证实，SARS-CoV-2 的垂直传播很少见，可能是由于胎盘组织中病毒复制效率低下所致。尽管大多数母亲的感染病程主要是良性的，并且垂直传播的风险可以忽略不计，但仍需要对妊娠期间 COVID-19 的后果保持持续警惕，因为母体对 SARS-CoV2 感染的免疫激活可能会对儿童的健康产生长期影响。
