Influenza virus Hemagglutinin (HA) and Neuraminidase (NA) (HA/NA)

The primary targets of influenza virus vaccines are the surface glycoproteins Hemagglutinin (HA) and Neuraminidase (NA) of the influenza A and B viruses [WHO, 2023]. Hemagglutinin is a lectin that mediates the binding of the virus to sialic acid receptors on the host cell surface and facilitates the fusion of the viral envelope with the endosomal membrane [StatPearls, 2023]. Neuraminidase is an enzyme that cleaves terminal sialic acid residues from glycoproteins, which is essential for the release of progeny virions from infected cells and for preventing viral clumping [Nature Reviews Microbiology, 2021]. Vaccines work by exposing the immune system to these antigens, thereby inducing the production of antibodies that neutralize the virus's ability to infect cells or spread within the respiratory tract [CDC, 2022]. While HA is the primary target for preventing infection, NA is an important secondary target that helps reduce the severity of the disease [Vaccines (Basel), 2020]. Understanding these targets is crucial for annual vaccine strain selection and the development of universal influenza vaccines that aim for broader protection across different viral subtypes [NIH, 2023].

Other names

Influenza virus vaccineFlu vaccineHemagglutininNeuraminidaseHANAInfluenza surface antigens

Vaccines induce the production of neutralizing antibodies that bind to the Hemagglutinin (HA) protein, preventing viral attachment to host cells, and the Neuraminidase (NA) protein, inhibiting the release of new viral particles [CDC, 2022; StatPearls, 2023].