This study clearly depicts that Every year, seasonal influenza viruses are estimated to cause globally >100 million episodes of illness and 870 000 hospitalizations for acute lower respiratory infection among children under 5 years of age.1 Children under 1 year of age are at the highest risk for influenza-attributable hospitalizations, and the youngest infants are frequently admitted due to sepsis-like symptoms.2-7 Influenza-associated childhood mortality rates are also highest among the youngest children.8, 9 Furthermore, children have a central role in the transmission of influenza in the community.Prevention of influenza in young infants is difficult. Influenza vaccines are licensed for use only in children older than 6 months of age, and the response to influenza vaccination in young infants is generally weaker than in older children.12 Maternal influenza vaccination during pregnancy reduces the risk of influenza in infants, but the duration of protection afforded by maternal antibodies is limited.

Reference link- https://onlinelibrary.wiley.com/doi/10.1111/irv.12820