Figure 2. Cumulative weekly estimates of the number and percentage of at-risk population with incident Zika virus infections computed with cobas Zika (Roche Molecular Systems, Inc., Pleasanton, CA, USA) individual nucleic acid testing results from Banco de Sangre de Servicios Mutuos and Banco de Sangre del Centro Médico de la Administración de Servicios Médicos, Puerto Rico, April 3–August 12, 2016. These estimates assume a mean viremia duration of 9.9 days (SD ± 3.9). Each weekly estimate is computed from all donation data collected from April 3 to the given week. Data for August 1–August 12, 2016 available only for Banco de Sangre de Servicios Mutuos. Error bars indicate 95% CIs.