Abstract

The United Kingdom has a national immunization programme which includes annual influenza vaccination in school-aged children, using live attenuated influenza vaccine (LAIV). LAIV is given annually, and it is unclear whether repeat administration can affect immunogenicity. Because LAIV is delivered intranasally, pre-existing local antibody might be important. In this study, we analysed banked samples from a study performed during the 2017/18 influenza season to investigate the role of pre-existing influenza-specific nasal immunoglobulin (Ig)A in children aged 6-14 years. Nasopharyngeal swabs were collected prior to LAIV immunization to measure pre-existing IgA levels and test for concurrent upper respiratory tract viral infections (URTI). Oral fluid samples were taken at baseline and 21-28 days after LAIV to measure IgG as a surrogate of immunogenicity. Antibody levels at baseline were compared with a pre-existing data set of LAIV shedding from the same individuals, measured by reverse transcription-polymerase chain reaction. There was detectable nasal IgA specific to all four strains in the vaccine at baseline. However, baseline nasal IgA did not correlate with the fold change in IgG response to the vaccine. Baseline nasal IgA also did not have an impact upon whether vaccine virus RNA was detectable after immunization. There was no difference in fold change of antibody between individuals with and without an URTI at the time of immunization. Overall, we observed no effect of pre-existing influenza-specific nasal antibody levels on immunogenicity, supporting annual immunization with LAIV in children.

Original languageEnglish
Pages (from-to)125-133
Number of pages9
JournalClinical and Experimental Immunology
Volume204
Issue number1
DOIs
Publication statusPublished - 1 Apr 2021

Keywords

  • Administration, Intranasal
  • Adolescent
  • Antibodies, Viral/immunology
  • Child
  • Female
  • Humans
  • Immunogenicity, Vaccine/immunology
  • Immunoglobulin A/immunology
  • Immunoglobulin G/immunology
  • Influenza A Virus, H1N1 Subtype/immunology
  • Influenza A Virus, H3N2 Subtype/immunology
  • Influenza Vaccines/administration & dosage
  • Influenza, Human/immunology
  • Male
  • Nasal Cavity/immunology
  • Vaccination/methods
  • Vaccines, Attenuated/administration & dosage
  • Virus Shedding/immunology

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