Figure 2. Virus RNA concentrations over time among health care personnel infected with pandemic (H1N1) 2009 virus, Seattle, Washington, USA. Each colored line represents a virus RNA concentration for an infected person tested from symptom onset until the first of 2 consecutive negative results by real-time reverse transcription–PCR (RT-PCR) for pandemic (H1N1) 2009 virus. Persons who had virus detected by real-time RT-PCR only once are indicated by solid circles. The lower detection limit of the real-time RT-PCR was 3 log10 copies/mL. Numbers of persons with virus RNA concentrations below the detection limit for each day after symptom onset are shown in parentheses below the x-axis. Sixteen infected persons were receiving oseltamivir.