自然史 (in the absence of HIv infection) People Exposed to TB NO TB INFECTION TB INFECTION Negative Skin Positive Skin Test Reactio st Reaction 50% During the first 2 years after infection, people NOT Infectious NOT Infectious vith te infection are at igh risk of developing Te disease TB DISEASE After the first 2036. INFECTIOU the risk is lower. but people with TB infection Remair Remain can develop Teg0%ease TB INFECTIoN at any point in their NO TB INFECTION NO TB DISEASE es. Some medical conditions increase the NOT Infectious NOT Infectious risk for tb disease24 自然史 (in the absence of HIV infection) 50% 50% 10% 90%