Scientists have recently developed an mRNA-lipid nanoparticle flu vaccine that protects against all known flu variants.
There are four types of influenza viruses but only the A and B viruses cause significant problems [Types of Influenza Viruses]. Influenza A viruses are the ones can have caused pandemics in the past and the current flu vaccinations are unlikely to offer a lot of protection since they are only directed toward the specific subtypes that are predicted to cause problems in the next flu season. The next global flu pandemic will probably come from a new influenza A virus that nobody predicted.