CD4 and AIDS: We observed that HIV disease progression measured by three endpoints varied by subtype, with C-infected volunteers tending to progress to (i) AIDS, (ii) viral load ≥100 000 copies/mL and (iii) CD4 T cell count ≤350 cells/μl faster than those infected with subtype A.23Because we also enrolled volunteers with incident HIV infection, typically within 1–2 months of their EDI, we were able to see patterns in acute retroviral syndrome; those infected with subtype A appeared to have worse symptoms shortly after infection, with greater report of headache, lymphadenopathy, fever and other symptoms.24