Vaccine Protection Through Placenta and Breastfeeding: The Unmet Topic in COVID-19 Pandemic

Abstract

The coronavirus disease 2019 (COVID-19) pandemic has turned pregnant women’s healthcare into a worldwide public health challenge. Although initial data did not demonstrate pregnancy as a more susceptible period to severe outcomes of acute severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infection, there are an increasing number of reports showing that not only pregnant women might be at significantly higher risk than non-pregnant women by COVID-19 but also the fetus. These findings may be related to adaptive changes that occur during pregnancy, such as the reduction in the residual respiratory capacity, the decrease in viral immune responses, and the increased risk for thromboembolic events. Additionally, despite the SARS-CoV-2 vertical transmission evidence being uncommon, maternal illness severity might reflect serious perinatal and neonatal outcomes. Thus, protecting the maternal–fetal dyad against COVID-19 is critical. Even though pregnant women initially were excluded from vaccine trials, several studies have provided safety and efficacy of the overall vaccine COVID-19 platforms. Vaccination during pregnancy becomes a priority and can generate benefits for both the mother and newborn: maternal neutralizing antibodies are transmitted through the placenta and breastfeeding. Moreover, regarding passive immunization, human milk contains other bioactive molecules and cells able to modulate the newborn’s immune response, which can be amplified after the vaccine. Nonetheless, many issues remain to be elucidated, considering the magnitude of the protective immunity transferred, the duration of the induced immunity, and the optimal interval for pregnant immunization. In this review, we assessed these unmet topics supported by literature evidence regarding the vaccine’s immunogenicity, pregnancy immune heterogeneity, and the unique human milk antiviral features.

What are the key pediatric public policy priorities as the COVID-19 pandemic persists?

“…COVID-19 antibodies are passed transplacentally, but are also present in breast milk, and both mechanisms likely confer an element of protection for the newborn infant. 12 , 13 We believe that cautionary statements about unfounded risks that might be attributable to the low-level presence of COVID mRNA in breast milk following COVID vaccination 14 are unwarranted, unsupported by any evidence, and may do harm by discouraging breastfeeding among vaccinated mothers or, conversely, discouraging immunization among women who plan to breast-feed.…”

El enigma del coronavirus – De pandemia a endemia COVID-19 - ¿Debemos seguir cuidándonos?

“…Cada vez hay más informes que muestran que no solo las gestantes podrían tener un riesgo significativamente mayor que las no gestantes por COVID-19, sino también el feto. Durante el embarazo existen cambios adaptativos, como la reducción de la capacidad respiratoria residual, la disminución de las respuestas inmunitarias virales y el mayor riesgo de eventos tromboembólicos (26) (27) . Este hallazgo podría deberse a la menor gravedad intrínseca de la variante SARS-CoV-2 ómicron en comparación con las variantes anteriores, a la inmunidad a nivel de población derivada de la vacunación y la infección previa, o a ambas cosas (28) .…”

“…Los anticuerpos neutralizantes maternos se transmiten a través de la placenta y la lactancia. En lo que respecta a la inmunización pasiva, la leche humana contiene otras moléculas bioactivas y células capaces de modular la respuesta inmunitaria del recién nacido, que pueden amplificarse tras la vacuna (26) . Y consideramos que en el futuro debemos estudiar cómo evolucionan las mujeres que se enfermaron con el SARS-CoV- observan pequeñas reducciones del parto prematuro en el primer (odds ratio 0,96; valor de p <0,0001), segundo (0,96) y tercer (0,97) meses de bloqueo, pero no en el cuarto mes de bloqueo (0,99), aunque con algunas diferencias entre países después del primer mes.…”

Children’s SARS-CoV-2 Infection and Their Vaccination

“…The transfer efficiency of antibodies from mother to fetus is also higher in the first and second trimesters compared to the third trimester when tested in both maternal and umbilical cord blood sites [ 38 ]. Maternal antibodies are also transferred via breastfeeding during lactation [ 39 ]. Children have been shown to have a durable immune response after COVID-19 infection.…”