Antibody Responses in Children and Elderly Persons Following Local or Parenteral Administration of an Inactivated Influenza Virus Vaccine, A2/Hong Kong/68 Variant

Abstract

Abstract We recently reported that the frequency and duration of serum antibody responses of elderly persons vaccinated by intranasal application of inactivated influenza virus vaccine were not significantly different from those seen following parenteral vaccination (1). The titers and duration of IgA antibody in nasal secretions were higher following nasopharyngeal vaccination than after subcutaneous immunization. The vaccine used in that study contained one type B and two type A2 components. Similar results were reported in another study with younger adults using a monovalent A2 influenza virus vaccine (2). With the introduction of a new, epidemic strain of influenza type A2 virus into an immunologically unprepared population, the responses to immunization with a vaccine containing a strain of virus representative of the type A2 variant causing outbreaks in the Far East are of special interest. Since elderly persons experience a high mortality rate from influenza and its complications, the present study was undertaken to evaluate antibody responses following intranasal or subcutaneous administration of inactivated monovalent vaccine in this age group.