Taleb SA, Al-Ansari K, Nasrallah GK, et al. - A major cause of lower respiratory infections among children is RSV, for which no vaccine is available. A leading vaccine candidate targeting different populations, including pregnant women, is the stabilized form of the fusion (F) protein, pre-F. Researchers examined hospitalized children with RSV infection with the aim to determine the magnitude and nature of RSV-directed maternal antibodies (matAbs) among them. They obtained 65 paired blood samples from RSV-infected children below 6 months of age, and their corresponding mothers. Analysis revealed the presence of only 14% of maternal antibodies in infants at hospitalization, with an average log₂ EP titer of 10.2 directed to both F-protein conformations. Greater neutralizing activity was evident in infants relative to that of binding antibodies. Relatively high NAb titers were observed in a third of infants, yet, they were hospitalized.