Vitamin C results in the decrease in the infectious activity of the influenza virus that is not due to the antioxidant activity of Vitamin C, but directly due to the virus-inhibiting activity of the Vitamin. It seems that Vitamin C can help to protect us from viral infections including viral influenza. Plus Vitamin C performs a dual function: it neutralizes free radicals, preventing them from activating, further blocks the activation of this pathway and thus boosts up our immune system.
Reference:
V.V. Zarubaeva, A.V. Slitaa, I.N. Lavrentyevaa, V.S. Smirnovb
Journal of Infection and Immunity = Infektsiya i immunitet 2017, vol. 7, no. 4, pp. 319–326
И 2017, Т. 7, No 4, с. 319–326