I would not deny this fact as there really a lot of medical practitioners who are telling lies to its community which is completely unacceptable and should deeply be condemned.
The only thing real is sick people, no-one to blame but themselves.
A strong immune system needs vitamins A, B6, B9, B12, C and D (Sun) Also the minerals zinc, selenium, iron and copper. Vitamin E to a lesser degree.
Most importantly wear a mask when you sit in front of your computer, it may have a virus.
Medical practitioners make money of sick people, more sick, more money.