Anxiety and stress can weaken the immune system
I don't know of any research that states that Klonopin reduces your immune system but I think there is some that this does occur to an extent when people come off of it. Anxiety itself, however can weaken your immune system as well as certain medical conditions. Here is a list of the side effects of Klonopin.
Klonopin
All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Klonopin:
Constipation; cough; dizziness; drowsiness; dry mouth; headache; increased saliva production; lightheadedness; loss of coordination; nausea; runny nose; tiredness.
Seek medical attention right away if any of these SEVERE side effects occur when using Klonopin:
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); behavior changes; blurred vision or other vision changes; change in appetite; change in the amount of urine produced or painful urination; changes in sexual function; confusion; dark urine; excessive hair growth or loss; fever, chills, or sore throat; hallucinations; irregular heartbeat; memory loss or problems; muscle aches or weakness; new or worsening mental or mood changes (eg, agitation, aggression, anxiety, behavior changes, depression, hostility, irritability, nervousness); new or worsening seizures; painful menstrual periods; pale stools; severe drowsiness; severe or persistent tiredness or weakness; shortness of breath; slow or shallow breathing; slurred speech or other speech problems; suicidal thoughts or actions; tremor; unusual bruising or bleeding; yellowing of the skin or eyes.
Nothing like this is listed as a side effect, but there are a lot of side effects that may make you feel bad like nausea. I would talk to your doctor, you may be lacking in a vitamin or mineral and bloodwork would show this. I have been on Klonopin for over two years and am never sick. Good luck, I hope you find some answers.