How strong can your immune system get naturally? I don't know where else to ask but yesterday I thought I might have been coming down with a cold as I couldn't stop sneezing, my throat was getting itchy, and nose was getting very stuffy, but I slept it off and today I somehow overcame all that and feel fine now. Due to circumstances, I haven't taken the vax and have just been taking my regular daily vitamins. I haven't gotten sick in ages too.