Figure 1.

 Transmission patterns of pandemic 2009 influenza A (H1N1) in families with young children. Shaded areas show the duration of respiratory symptoms (cough, runny nose, or sore throat with or without fever) during laboratory‐confirmed influenza. Viral copy numbers are shown. Prospective follow‐up was started on day 0. Families were followed until day 14, but symptoms until day 8 are shown here for readability of the figure. All samples taken on day 14 were negative for influenza virus. Shaded areas in Family 4 are drawn from the onset of symptoms to last positive sample, because of missing data about the duration of symptoms.