Similarly, to explore whether APD slopes varied by mode of infection, set-point viral load, or rate of CD4+ T cell decline, we compared the infant-trained hierarchical model to models containing the respective slope-varying effects of interest (e.g. a mode-of-infection-specific slope-modifying term, a set-point-viral-load-specific slope-modifying term, etc.)by calculating Bayes factors. The gene discussed is CD4; the disease is infection.