Might it be that a multivitamins help treat the flu?

Not a FLU treatment.: If you have the flu hydrate well w water, herbal teas, soup or juice. Drink sufficiently to have pale to light yellow urine. You can use pain relievers like tylenol (acetaminophen) or nsaid’s. Rest a lot! in some situations antiviral medications (tamiflu, relenza, flumadine) may be prescribed within the first couple of days of symptoms to hasten healing or they can be used after flu exposure to prevent illness.