Is there a gene/disease or other that can identify why l haven't caught cold/flu in 5yrs? used to catch them regularly before. can something trigger the resistance? fibromyalgia type symptoms since the same 5yrs. any thoughts appreciated?

In the Covid era,many people have not caught cold or had influenza for several years because of some masking& some ongoing social distancing&more hand washing than they used to do. Also older people have acquired more immunity to the many common cold virusesthan younger people as the years go on. The etiology of fibromyalgia remains elusive. Most clinicians do not consider it anautoimmune disorde