>Average_Cat_Lover · 2 hr. ago
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>How is the development of flu vaccines administered via others ways (nasal spray, droplet) going? Is there a significant difference in vaccine technology used (eg: deactivated virus, egg protein) between them and the normal vaccine?

There are several types of FDA-approved influenza virus vaccines in the US (summarized at https://www.cdc.gov/flu/prevent/different-flu-vaccines.htm ). Advances in influenza virus vaccine technology are ongoing (summarized at https://www.cdc.gov/flu/prevent/advances.htm#vaccine-advances ). Different vaccine formulations have different properties (e.g. egg protein vs egg-free, inactivated vs live-attenuated, etc). While the unadjuvanted, inactivated, intramuscularly-administered influenza vaccine is most common, there are a range of FDA-approved influenza virus vaccines against seasonal influenza viruses.