Functional immune response to influenza H1N1 in children and adults after live attenuated influenza virus vaccination

Abstract

Influenza virus is a major respiratory pathogen, and vaccination is the main method of prophylaxis. In 2012, the trivalent live attenuated influenza vaccine (LAIV) was licensed in Europe for use in children. Vaccine‐induced antibodies directed against the main viral surface glycoproteins, haemagglutinin (HA) and neuraminidase (NA) play important roles in limiting virus infection. The objective of this study was to dissect the influenza‐specific antibody responses in children and adults, and T cell responses in children induced after LAIV immunization to the A/H1N1 virus. Blood samples were collected pre‐ and at 28 and 56 days post‐vaccination from 20 children and 20 adults. No increase in micro‐neutralization (MN) antibodies against A/H1N1 was observed after vaccination. A/H1N1 stalk‐specific neutralizing and NA‐inhibiting (NI) antibodies were boosted in children after LAIV. Interferon γ‐producing T cells increased significantly in children, and antibody‐dependent cellular‐mediated cytotoxic (ADCC) cell activity increased slightly in children after vaccination, although this change was not significant. The results indicate that the NI assay is more sensitive to qualitative changes in serum antibodies after LAIV. There was a considerable difference in the immune response in children and adults after vaccination, which may be related to priming and previous influenza history. Our findings warrant further studies for evaluating LAIV vaccination immunogenicity.

Immune Responses Elicited by Live Attenuated Influenza Vaccines as Correlates of Universal Protection against Influenza Viruses

“…The study showed no correlation between NI and HI antibody titers, suggesting that independent detection of HI antibodies and NI antibodies provide a more accurate assessment of LAIV immunogenicity. Another study demonstrated that LAIV resulted in significant increases in NI antibody titers in most of children and adults in the presence of preexisting NI antibodies [43]. Animal studies also demonstrated robust induction of cross-reactive NA antibodies following LAIVs.…”

“…This result suggests that preexisting immunity to the HA stalk can be beneficial for the induction of HA stalk antibodies by LAIVs in humans. The following study investigated the functionality of HA stalk antibodies after LAIV in children and adults [43], in which LAIV-induced HA stalk antibodies exhibited viral neutralizing and ADCC activity, which was more significant in children than adults. While it remains unclear whether HA stalk antibodies induced by LAIVs contribute to protection, animal and human studies together demonstrate that LAIVs are able to induce HA stalk antibody responses, providing important implications on developing LAIV-based UIVs.…”

SARS-CoV-2 infections in children and young people

“…Generally, CYP with systemic inflammatory conditions are at an increased risk for infections, which is caused by general immune dysregulation and immune modulating/suppressive treatments [ [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] ]. Frequently, immune responses to virus infections and vaccinations are reduced and prolonged viral shedding is common [ [58] , [59] , [60] , [61] , [62] , [63] , [64] , [65] , [66] , [67] ]. To date, reliable data in relation to SARS-CoV-2 do not exist [ 68 ].…”

COVID-19 bei Kindern und Jugendlichen

“…Generell ist festzustellen, dass Kinder und Jugendliche mit Autoimmunerkrankungen als Resultat der generellen Immundysregulation im Rahmen der Grunderkrankung und als Nebenwirkung immunmodulierender Therapien ein gesteigertes Infektionsrisiko aufweisen [43][44][45][46][47][48][49][50][51][52][53][54]. Immunantworten auf Virusinfektionen und Impfungen sind oft abgeschwächt, Infektionen häufiger und die Virusausscheidung in der Regel verlängert [55][56][57][58][59][60][61][62][63][64].…”