Influenza virus hemagglutinin and neuraminidase (GC Flu formulation) (HA/NA (GC Flu))

The influenza virus strains included in the GC Flu formulation represent the specific viral antigens selected annually by the World Health Organization (WHO) for seasonal vaccine production [1][2]. These formulations typically include hemagglutinin (HA) and neuraminidase (NA) proteins from Influenza A (H1N1 and H3N2) and Influenza B (Victoria and Yamagata lineages) strains [1]. HA is a surface glycoprotein that mediates viral binding to sialic acid receptors on host respiratory cells, facilitating viral entry [3]. NA is an enzyme that cleaves sialic acid residues to facilitate the release of progeny virions from infected cells and prevent viral aggregation [3]. By introducing these inactivated or subunit antigens, the GC Flu vaccine stimulates the host immune system to produce neutralizing antibodies, primarily targeting the globular head of HA [4]. This target is critical for preventing seasonal influenza-related morbidity and mortality, particularly in high-risk populations such as the elderly and immunocompromised [4]. The efficacy of the formulation depends heavily on the antigenic match between the vaccine strains and the viruses circulating during the flu season [2]. GC Flu is available in both trivalent and quadrivalent formats to provide broad protection against multiple circulating lineages [1].

Other names

GC Flu Quadrivalent antigensSeasonal influenza vaccine strainsInfluenza A and B antigensGC Flu trivalent antigens

The vaccine antigens induce the production of strain-specific neutralizing antibodies, primarily targeting the hemagglutinin protein to prevent viral attachment and entry into host cells [4]. Antibodies against neuraminidase may also be produced, which help inhibit the release of new viral particles from infected cells [3].