Maela is an overcrowded and relatively closed refugee camp and therefore might be considered an ideal location for a novel infl uenza virus to cause an explosive outbreak. However, the number of confi rmed cases indicated that no major outbreak occurred in 2009. After the fi rst case of pandemic (H1N1) 2009 was identifi ed in August, these cases increased modestly in September, then substantially declined during October. Overall, only 25% of all infl uenza A viruses were determined to be the pandemic strain. However, supportive data show a change of the predominant infl uenza virus. In late August 2009, seasonal infl uenza A (H1N1) was the predominant circulating virus; during the subsequent 2 months, only cases of pandemic (H1N1)