Hi !
Before you dive into taking multi-vitamins, first and foremost you may want to look into your nutrition and diet. As long your nutrition is complete you don't have to worry about loss of immunity.
Vitamin and Minerals are only recommended after you have a complete blood profile, so that you and your doctor know what you are deficient in and what your nutrition is lacking.
All Vitamins and Minerals play an important role in Immune function, with more importance to Vitamin C ,
B12, and D.
Any MultiVitamins over the counter provide cover for most of the Vitamins.
You should also be aware, over dosing on Vitamins, can create problems of their own.
Next Steps
Consult a Doctor and Do a
Complete Blood CountHealth Tips
Healthy Diet including Fruits and Berries.