How to strengthen immunity? Can I take ImmuCell defense every day?

Good morning, I have been using ImmuCell defense for 2 weeks for 4 capsules a day. I am treated for hypertension and Hashimoto's (I take Co-Prestarium and Percentile and Euthyrox). Can I safely use these capsules every day, without taking a break, i.e. take 90 pcs. And is it enough? I often catch various infections, I am 57 years old. None of the doctors I am treating with was able to give me a definite answer. I count on your help. Best regards