My only proof from personal experience was when my wife got it, and lost her smell. Never having heard of that symptom for flu before, that was my personal proo

My only proof from personal experience was when my wife got it, and lost her smell. Never having heard of that symptom for flu before, that was my personal proof. Until a colleague told me he lost his smell 2 years ago after a serious flu. I still do believe the virus exists, but not having the equipment to look at it myself how can I be absolutely certain?