Each year, influenza A infections have caused tremendous death rate as high as 300,000-500,000 globally. Although
there are effective anti-influenza agents and vaccines, high mutational rate among influenza A viruses renders dramatic
decline in the effectiveness of anti-influenza agents or vaccines in certain individuals. The situation is further complicated
by limitations in influenza vaccine production, for instance, long production period, limited vaccine capacity and lack
of cross-protection against various influenza A virus strains. To solve these issues, development of universal influenza
vaccine based on conserved antigens such as non-stuctural protein 1 (NS1) has been endeavoured. NS1 protein is highly
conserved in all influenza A virus strains known by far, produced abundantly on infected cell surfaces and responsible for
maintaining virulence. Furthermore, cytotoxic T-lymphocytes that are active against NS1 were also reported to be able
to avoid shedding of influenza in hosts. To better inhibit influenza infections, oral immunization has long been proposed
due to feasibility of this method to be implemented and safer for recipients while able to target influenza A viruses from
the entry point. Lactobacillus has been vastly studied for its roles as bacterial carrier in oral vaccine development due
to its significant probiotic properties. For examples, stimulation of immune responses in oral and airway mucosal layers,
high colonization in oral and airway mucosal layers and great natural adjuvant effects. In this light, influenza universal
oral vaccine developed using NS1 dan Lactobacillus should be further studied in influenza oral vaccine design.