In short, the injectable flu vaccine DOES NOT SHED!, in the sense that the vaccinated person spreads the virus from the vaccine. But the nasal spray, because it is a live virus, can shed. Those vaccinated, when infected with the flu, SHED/SPREAD more of the naturally acquired infection.

For a more in-depth explanation click the link to read my article. I hope this helps! https://thewilddoc.com/does-the-flu-vaccine-shed-clearing-up-the-myths-and-misunderstanding/