Figure 2.

(a) Distribution of volunteers diagnosed with hyperacute HIV-1 infection by AHI symptoms; (b) a schematic illustration of the distribution of AHI symptoms for all volunteers (black curve) and by grouping of volunteers resulting from latent class analysis (LCA, for those without acute retroviral syndrome, [ARS, blue] and for those with ARS [red]). The numbers denote median (interquartile ranges) symptoms per volunteer for all volunteers (in black), for those without ARS (in blue) and for those with ARS (in red); and (c) Graph comparing the distribution of AHI symptoms between volunteers that were defined to be with and without ARS (Fisher exact test P < .05 [*], P < .01 [**], and P < .001 [***], N = 55). ARS was defined based on the 11 AHI symptoms and other unobserved linkages between symptoms using LCA. Incremental latent group models were assessed to predict the goodness of fit. The model with 2 latent groups was the best fit as it had the lowest BIC value (660.5) compared to 3 (678.6), 4 (699.2), or 5 (714.7) groups. Volunteers were grouped based on their predicted posterior probabilities into those with ARS (n = 31 [56%]) and those without ARS (n = 24 [44%]). Abbreviations: AHI, acute human immunodeficiency virus type 1; ARS, acute retroviral syndrome; CI, confidence interval; HIV-1, human immunodeficiency virus type 1; LCA, latent class analysis.