Antibody Responses in Serum and Nasal Secretions According to Age of Recipient and Method of Administration of A2/Hong Kong/68 Inactivated Influenza Virus Vaccine

Abstract

Neutralizing antibody responses in serum and nasal secretions following vaccination with A2/Hong Kong/68 inactivated influenza virus vaccine were compared according to age and route of administration. Among all of the age groups receiving one dose of vaccine subcutaneously or intranasally, children developed the greatest frequency of antibody response and increase in mean antibody titer in both serum and nasal secretions. In adults, vaccination by either route induced less serum antibody and was ineffective in inducing nasal antibody. Neutralizing activity of nasal wash specimens was removed by absorption with antiserum directed against secretory piece. Vaccination also resulted in rises in antibody titer in serum and nasal secretions to A/Equi-2 virus, a type known to be antigenically related to A2/Hong Kong/68 influenza virus.