Take some vitamin C, vitamin D, and some zinc (balanced with copper) along with some exercise daily and your immune system will be top notch.
All good points. To that I would cut down on sugar because sugar stresses the immune system, and also vitamin D preferably from moderate sunshine. Sunshine is more than just an enabler of vitamin D. It actually stimulates immune cells.
I am GenX and rarely serious illness. Caught walking pneumonia in college ( i didn’t think it was real until I got it). Since then, i get an sinus infection if i get rained on or a strong wind blowing = something to do with my ears.
At 35 I started taking Vitamin D3 (10,000 IU) and C daily. Doctor told me I had too much D in my system. I ignored him.
No flu or cold for 25 years = had a couple of sinus infections because I didn’t take proper precautions in rain/wind. Lived all over the country the previous 25 years avoiding infections until I moved to AZ three years ago - I get something every 3 months. I have to travel to Los Angeles every three months and come back with an illness - maybe that is the connection