ABSTRACT
Vaccinations are one of the greatest achievements for protecting public health. Vaccines given to pregnant women protect not only the pregnant woman, but also the newborn. Pregnant women are disproportionately strongly affected by infections. The conflicting demands on the maternal immune system during pregnancy geared toward maintaining fetal immune tolerance make a rapid and effective immune response against pathogens more difficult. This dynamic state of immune adaptation predisposes pregnant women to more severe disease progression. Vaccination can prevent infection or a serious course of disease. As a result, the risk of premature birth and other serious pregnancy complications that can have lifelong consequences for both mother and child also decreases. After birth, when the newborn must first develop an adaptive memory for a hitherto unknown, antigen-rich environment, it is particularly vulnerable to infections and resulting complications. The transfer of maternal antibodies across the placenta protects infants who are too young to be vaccinated. When breastfeeding, this continues through antibodies in breast milk. For the vaccinations recommended by the Standing Vaccination Committee (STIKO) during pregnancy (influenza, pertussis, coronavirus disease [COVID]-19), there is clear evidence from various observational and prospective studies that they protect mother and child either from infection or from a severe disease course. The following article gives an overview of the vaccination strategy for pregnancy and summarizes the scientific data on effectiveness of the vaccinations currently recommended during pregnancy.Copyright © 2022, The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.
ABSTRACT
Pathogens are a major threat to maternal health and the progression of pregnancy. The immune response during normally progressing pregnancies, primarily the suppression of inflammation, likely accounts for this high susceptibility of pregnant women to infections. An increased morbidity and mortality related to influenza, COVID-19 and malaria has been reported for pregnant women, compared to non-pregnant women. Especially influenza infections during pregnancy have been well studied, as humans are severely and recurrently affected by seasonal epidemics and random pandemics. Besides severe maternal symptoms such as acute cardiopulmonary events, pneumonia, and acute respiratory distress syndrome, maternal influenza infection also causes foetal complications, such as intrauterine growth restriction, preterm birth or even foetal death. However, vertical transmission of the influenza virus across the placenta and infection of the foetus has not been observed, suggesting that the pregnancy pathologies are maternally derived. In addition to influenza-mediated adverse conditions, the recent COVID-19 pandemic has underscored that infection with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) can also lead to severe illnesses in pregnant women, accompanied by a higher risk for foetal loss or preterm birth. Fortunately, with the ongoing pandemic, large cohort studies and meta-analyses revealed that vertical transmission and related fetal infection is a rare complication affecting only 1-3% of SARS-CoV-2 infections in pregnancy. These low risk for placental infection is likely due to the inefficient SARS-CoV-2 virus replication in placental tissues. Since understanding SARS-CoV-2-related pathogenicity during pregnancy is highly relevant, we initiated a study early in 2020, to which we have recruited more than 160 pregnant women with COVID-19. Our comprehensive placental analyses unearthed a paucity of SARS-CoV-2 viral expression ex vivo in term placentae under acute infection and in convalescent pregnant women. Furthermore, we could show inefficient SARS-CoV-2 replication in placental tissues in vitro, which provides a rationale for the low ex vivo viral expression. We detected specific SARS-CoV-2 T cell responses in mothers within a few days upon infection, which is undetectable in cord blood. Reports by others have shown that maternal SARS-CoV-2 during pregnancy may cause placental insufficiency, defined by increased perivillous fibrin deposition, histiocytic intervillositis and trophoblast necrosis. These changes can cause extensive placental damage leading to placental malperfusion and insufficiency that is incompatible with intrauterine survival. Considering that multiple SARS-CoV-2 variants of concern which emerged until today may affect pregnant women differently and bear a differential risk for pregnancy complication. This, continuous vigilance is needed in order to provide best protection of the highly vulnerable group of pregnant women and their unborn children. Trial registration number