Assess the Correlation With Severe Respiratory Syncytial Virus Disease in the First 6 Months in Children With Congenital Heart Disease and Maternal Ac-AntiVSR Titers During Pregnancy

Passive transplacental immunity against the respiratory syncytial virus (RSV) appears to mediate infant protection during the first 6 months of life (1). Observations of environmental exposure in pregnant women during an RSV epidemic could influence these children's susceptibility to infection by offering levels of antibodies that are transferred to the fetus. However, there is no prospective study in the population at risk such as children with congenital heart disease, as well as the effective levels of anti-RSV immunoglobulin G (IgG) as protective biomarkers for RSV infection after delivery (2) Justification The most serious evolution of the clinical disease of acute RSV bronchiolitis in children under 6 months of age is related to lower exposure of the pregnant woman to the RSV epidemic. With maternal immunization through natural exposure, it is logical to relate protection to children for severe RSV disease. However, it is not proven (3). 1. \- Nandapalan N, Taylor CE, Greenwell J, et al. Seasonal variations in maternal serum and mammary immunity to RS virus. J Med Virol. 1986;20(1):79-87. doi:10.1002/jmv.1890200110 2. \- Stensballe LG, Ravn H, Kristensen K, Meakins T, Aaby P, Simoes EA. Seasonal variation of maternally derived respiratory syncytial virus antibodies and association with infant hospitalizations for respiratory syncytial virus. J Pediatr. 2009;154(2):296-298. doi:10.1016/j.jpeds.2008.07.053 3. \- Ramos-Fernández JM, et al. Does exposure of pregnant women to epidemic respiratory syncytial virus affect the severity of bronchiolitis? Enferm Infec Microbiol Clin. 2017. https://doi.org/10.1016/j.eimc.2018.07.002)