Only Vitamin D could be of help and also Vitamin B to a certain extent. Ever since Covid started, since a year ago, I had written
several times here to take Vitamin D 1000 - 2000 IU every day. Vitamin D has been given since the SARS epidemic, and helps in all respiratory diseases and it was noticed that those old people who died from Covid first had low Vitamin D levels. During SARS old people were administered with 20,000 IU of Vitamin D injected IV as a prophylactic treatment.
Many of us can be Vitamin D deficient. Did any of you have checked your levels anytime?
Also Vitamin B can be of help as it can regulate our innate and adaptive immune responses and also helps to reduce pro-inflammatory cytokine levels. So there is some basis for it.
You can forget the rest of the elements in the Periodic table and various tablets that's on the Fakebook which are pure marketing strategies. These are only used in India and just based on hearsay and not on evidence.

Zincovit and Vitamin C does not help. If anyone can show me a study, please go ahead.