A Subunit-based Influenza/SARS-CoV-2 Omicron Combined Vaccine Induced
Potent Protective Immunity in BALB/c Mice
Abstract
Infection with influenza A virus (IAV) and severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) poses a significant risk to human
life, health, and the global economy. Vaccination is one of the most
effective strategies in the fight against infectious viruses. In this
study, we, for the first time, have evaluated the immunogenicity and
protective effect of an influenza/SARS-CoV-2 Omicron subunit combined
vaccine adjuvanted with MF59 and administered to BALB/c mice. Results
showed that the combined vaccine induced high levels of IgG, IgG
1, and IgG 2a antibodies, as well as
influenza A H1N1/California/2009 virus-specific
hemagglutination-inhibiting antibodies in BALB/c mice. Moreover, this
subunit combined vaccine induced high titers of neutralization
antibodies against SARS-CoV-2 Omicron BA.5 pseudovirus and effectively
reduced the viral load of authentic SARS-CoV-2 Omicron BA.5.2 variant in
the cell culture supernatants. These results suggested that this subunit
combined vaccine achieved protective effect against both H1N1
A/California/07/2009 strain and SARS-CoV-2 Omicron BA.5.2 variant. It is
therefore expected that this study will establish the scientific
foundation for the next-step development of combined vaccines against
other strains or variants of IAV and SARS-CoV-2.