Duration of incubation affects subsequent rate of HIV disease progression

Dr Phillipe Vanhems and associates at the Universite Claude Bernard in Lyon investigated the relationship between incubation time before the onset of acute HIV-infection and time to an AIDS defining event. The prospective study of 70 patients identified the date of HIV-infection, onset of symptomatic acute infection and time to an AIDS defining event.

Median incubation time (from ‘inoculation’ to acute infection) was 21.5 days with a range of 5 to 70 days. The duration and severity of acute infection was found to be unrelated to the duration of incubation. There was, however, a significant association between the duration of incubation and time to first AIDS defining event. Median time to AIDS was 3.82 years for patients whose incubation time was less than the median and 5.05 years for patients whose incubation time was above the median.

The mechanism by which incubation time affects rate of disease progression is unknown but may involve variations in both host immunity and viral replicative capacities.

Vanhems P; Hirschel B; Phillips AN et al. Incubation time of acute human immunodeficiency virus (HIV) infection and duration of acute HIV infection are independent prognostic factors of progression to AIDS. J Infect Dis 2000 Jul;182(1):334-7.