The PPV23 is protective against all-cause pneumonia and pneumococcal disease in HIV-infected adults, although data vary as to whether the protective benefit is irrespective of CD4+ count above a particular threshold, or dependent on HIV viral load at time of vaccination.23 Results from a randomised placebo-controlled trial of PPV in HIV-infected subjects conducted in Uganda found an increase in all-cause pneumonia in the vaccine arm.24 As a result, some international guidelines do not recommend vaccination with PPV among HIV-infected adults with CD4+ counts less than 200 cells/μL. The gene discussed is CD4; the disease is susceptibility to pneumonia measurement.