Viral dynamics in primary HIV-1 infection

Objectives: To study the natural course of viremia during primary HIV infec tion (PHI). Method: Eight patients were followed from a median of 5 days from the onset of PHI illness. Plasma HIV-1 RNA levels were measured frequently and the r esults were fitted to mathematical models. HIV-1 RNA levels were also monit ored in nine patients given two reverse transcriptase inhibitors and a prot ease inhibitor after a median of 7 days from the onset of Pi-II illness. Results: HIV-1 RNA appeared in the blood during the week preceding onset of PHI illness and increased rapidly during the first viremic phase, reaching a peak at a mean of 7 days after onset of illness. This was followed by a phase of rapidly decreasing levels of HIV-1 RNA to an average of 21 days af ter onset. Viral density continued to decline thereafter but at a 5- to 50- fold lower rate; a steady-state level was reached at a median of 2 months a fter onset of PHI. Peak viral density levels correlated significantly with levels measured between days 50 and 600. Initiation of antiretroviral treat ment during PHI resulted in rapidly declining levels to below 50 copies/ml. Conclusions: This study demonstrates the kinetic phases of viremia during P HI and indicates two new contributions to the natural history of HIV-1 infe ction: PHI peak levels correlate with steady-state levels and HIV-1 RNA dec lines biphasically; an initial rapid decay is usually followed by a slow de cay, which is similar to the initial changes seen with antiviral treatment. (C) 2000 Lippincott Williams & Wilkins.