- Viral neuraminidase is an enzyme on the surface of the influenza virus that cleaves sialic acid residues on the host cell membrane and viral glycoproteins.
- This action prevents newly formed virions from aggregating at the host cell surface, allowing their efficient release and spread to infect new cells.
- Without neuraminidase activity, viruses remain attached to the host cell, limiting infection. This function is distinct from viral attachment or genome integration, making Option 1 correct.

Reference: Murray et al., Medical Microbiology, 8th Edition, Chapter 27/pg 575