HIV RNA patterns over time after seroconversion. Scatterplot of HIV RNA values after seroconversion (grey points), together with the fitted least squares curve (i.e. average HIV RNA values; thin grey line) and the fitted curve from the random effects model (i.e. average HIV RNA patterns; thick black line, with 95% confidence intervals). Average patterns for the groups defined by progression times (in years) are shown as well (dashed grey lines).