CD4 and tuberculosis: The study found that several factors were protective against developing new TB among HIV patients, including being female and having CD4 count between 350 cells/μl to 500 cells/μl both of which were protective by 58%, with IRRs of 0.42 (95% CI 0.34–0.50) and 0.42 (95% CI 0.21–0.87), respectively.