CD4 and infection: Because our model estimates a time of infection of at least 8 years for patients with CD4-count lower than 200 cells/μl (Figure S3), we can infer that a 30% of late presenters corresponds with a testing coverage that allows detection of 70% of patients before 8 years of infection; which, according to the model, corresponds to a testing rate close to 10% (Figure 7).