Immunogenicity of Split Inactivated Quadrivalent Influenza Vaccine in Adults with Obesity in the 2017/2018 Season

Background: Obesity is associated with susceptibility to severe influenza infection and several disturbances of the immune response to the influenza vaccine. However, the effect of obesity on the immunogenicity of the influenza vaccine is not fully understood. Our objective here was to assess the immunogenicity of the split, inactivated quadrivalent influenza vaccine (QIV) in Polish adults with obesity. Material/Methods: Fifty-three subjects with obesity aged 21-69 years were vaccinated with the QIV in 2017/2018 season. Antibody titers against the 4 vaccine strains were measured using the hemagglutination inhibition (HI) assay. The mean fold antibody increase (MFI), seroprotection rate (protection rate, PR), and seroconversion rate (response rate, RR) were calculated to assess vaccine immunogenicity. Results: The vaccine elicited a significant increase in the anti-HI titers against the QIV antigens. The MFI, PR, and RR for the QIV antigens also reached the required age-specific values, indicating the QIV meets current immunogenicity criteria. Individuals with class I and class II/III obesity had similar anti-HI titers, MFI, PR, and RR to each of the vaccine strains. Adults aged <60 years had similar anti-HI titers, MFI, PR, and RR to the QIV strains to those aged >= 60 years. Conclusions: Our results indicate that the split virion, inactivated QIV is immunogenic in adults with obesity regardless of their degree of obesity and age (ie, <60 and >= 60 years).