Comparative Assessment of Reactogenicity and Immunogenicity of Commercial Influenza Inactivated Vaccines: Polymer-Subunit Grippol plus, Subunit Influvac, Split Vaccine Waxigrip

Abstract

Objective. To compare the reactogenicity and immunogenicity of inactivated influenza vaccines: Grippol Plus polymer subunit vaccine, Influvac subunit vaccine, and Vaxigrip split vaccine as part of influenza prevention in people aged 18 - 55 with no pre-existing conditions. Materials and methods. Comparative study of three groups of volunteers with no pre-existing conditions using coded serum samples. Randomisation: 1:1:1. Group 1:100 people vaccinated with Grippol® Plus, Group 2:100 people vaccinated with Influvac, Group 3: 100 people vaccinated with Vaxigrip. The study looked into the levels of specific hemagglutination-inhibition antibodies to influenza viruses in a standard hemagglutination inhibition assay (HAI), with the coding of sera obtained before the vaccination and 28 days post-vaccination. The seroconversion rate (share of patients with the antibody titer increase of more than 4x) and seroprotection rate (share of patients with antibody titer > 1:40) were measured. Reactogenicity was evaluated based on the intensity of systemic and local reactions during the first five days post-vaccination. Results. Reactogenicity: in general the number and intensity of systemic and local reactions in all the groups was insignificant, the reactions were mild and required no treatment with medications. Tolerability levels were high. There was a reliable decline in local reactions to subunit vaccines over time. Immunogenicity: the seroprotection rate for the A/H1N1 strain on day 28 post-vaccination was 95.0% for the Grippol Plus group, 95.0% for the Influvac group, and 96.0% for the Vaxigrip group. The seroprotection rate for the A/H3N2 strain on day 28 post-vaccination was 90.9% for the Grippol Plus group, 90.0% for the Influvac group, and 96.0% for the Vaxigrip group. The seroprotection rate for the B strain on day 28 post-vaccination was 99.0% for the Grippol Plus group, 100.0% for the Influvac group, and 100.0% for the Vaxigrip group. Conclusion: the study found that the Grippol Plus, Influvac, and Vaxigrip vaccines have similar efficacy in vaccination against the A/H1N1, A/H3N2, and В strains 28 days post-vaccination. All the vaccines tested were in line with the CPMP requirements to the immunogenicity of human influenza vaccines. All the vaccines had a similar safety profile, but the incidence of injection site pain, swelling and itching was reliably lower in those vaccinated with the Grippol Plus and Influvac vaccines as compared to the Vaxigrip vaccine.