The Importance of Vaccinating Children and Pregnant Women against Influenza Virus Infection

Abstract

Influenza virus infection is responsible for significant morbidity and mortality in the pediatric and pregnant women populations, with deaths frequently caused by severe influenza-associated lower respiratory tract infection and acute respiratory distress syndrome (ARDS). An appropriate immune response requires controlling the viral infection through activation of antiviral defenses, which involves cells of the lung and immune system. High levels of viral infection or high levels of inflammation in the lower airways can contribute to ARDS. Pregnant women and young children, especially those born prematurely, may develop serious complications if infected with influenza virus. Vaccination against influenza will lead to lower infection rates and fewer complications, even if the vaccine is poorly matched to circulating viral strains, with maternal vaccination offering infants protection via antibody transmission through the placenta and breast milk. Despite the health benefits of the influenza vaccine, vaccination rates around the world remain well below targets. Trust in the use of vaccines among the public must be restored in order to increase vaccination rates and decrease the public health burden of influenza.

Protective Intranasal Immunization Against Influenza Virus in Infant Mice Is Dependent on IL-6

“…Infant immunity remains an important area of focus due to significant existing morbidity related to infectious disease. Influenza infection remains a major challenge among infections in children under five years of age (56). While historically it is believed to be due to an inappropriate T/B cell immune response, pathology and resolution of primary influenza virus infection is not dependent on the adaptive immunity but requires innate immunity (57).…”

One step closer to influenza vaccine inclusiveness

“…Studies on the use of RIV in pregnant women are limited 4 . Another critical advantage of flu vaccination during pregnancy is that vaccinated pregnant women also protect against flu to their infants during the first 6 months of life, through the transplacental transfer of influenza‐specific maternal IgG 2 . A reduction of 72% of laboratory‐confirmed influenza hospitalizations in the first months of life has been observed in infants born to women who have received the flu vaccine during gestation 8 .…”

“…Although flu may have an uncomplicated clinical course, it could also present itself as a severe condition. Epidemiological data showed that severe complications of flu infection occurred in more than 3 million people every year, with hundreds of thousands of deaths 2 . The risk of complications, hospitalization, and poor outcome is higher in specific categories of patients (ie, younger children, the elderly, pregnant women, immunocompromised patients, and people affected by chronic conditions eg, asthma) 3 .…”

“…The risk of complications, hospitalization, and poor outcome is higher in specific categories of patients (ie, younger children, the elderly, pregnant women, immunocompromised patients, and people affected by chronic conditions eg, asthma) 3 . It goes without saying how influenza vaccination is essential in the vulnerable hosts 2 . In agreement with the Advisory Committee on Immunization Practices (ACIP), we, as the Italian Pediatric Immunology and Allergology Society (SIAIP) Vaccine Committee, recommend flu vaccination for all people aged ≥ 6 months, unless they have specific contraindications.…”

Influenza Virus and Vaccination

“…Disturbingly, the authors indicated that despite the benefits of the influenza vaccine, vaccination rates around the world remain well below targets. The constantly changing HA antigenicity of the influenza virus, along with the complexity of serological responses induced by influenza infections in the immune system, muddies efforts to interpret serology testing results or develop more effective vaccines [3]. In order to improve the safety of the live-attenuated influenza vaccine (LAIV) and make it available to a broader population (it is currently not recommended for children under the age of two, immunocompromised individuals, the elderly, and pregnant adults), Hilimire et al have demonstrated that the influenza A virus master donor virus (MDV) A/Ann Arbor/6/60 H2N2 LAIV can inhibit host gene expression using both the PA-X and NS1 viral proteins.…”