I am a 23 year old female who was born in Taiwan and received the BCG vaccine before coming to the US. Recently, I was exposed to someone with active TB who was living in the same household as I for a period of time. He is currently in quarantine, asymptomatic and receiving treatment. I tested with 2 positive TB skin tests (the first one 7mm and second one 12 mm) each one week apart, however 2 chest xrays performed showed no abnormal findings. My quantiferon test result was "indeterminate", and I was told by the physician at the TB clinic that even if the quantiferon result was negative, the test is inconsistently accurate in Southeast Asians. I have not experienced any TB related symptoms (night sweats, cough, hemoptysis, etc).

I know there is a possibility that my positive skin tests are ONLY due to my previous BCG vaccine creating a reaction and that I have not been latently infected with TB. However, the physician told me that there is a chance that I have been latently infected, and it just has not shown up on my xray. Given the severe side effects and lengthy course of Isoniazid, I am very hesitant to continue treatment, as I just started yesterday and already experienced significant drowsiness and a severely debilitating headache that has lasted all day. I know Rifampin is an alternative treatment if I cannot tolerate INH, but also has significant side effects as well.

Given this history, would you recommend that I pursue prophylactic treatment? or do you believe that I am most likely not infected and my positive skin tests are due to my previous BCG vaccine reacting? I have a strong medical background so please feel free to give as detailed an explanation as you would like.

Thank you.