Viral hemagglutinin (HA) polymorphisms in specimens of patients with positive detection of pandemic influenza A/H1N1/2009 viral RNA outside the respiratory system.

a+ = Severe cases; − = mild cases;bViral load is based on the quantitative PCR of the M gene. If multiple blood samples were tested, the highest viral load is shown;cD = Aspartic acid; G = Glycine; N = Asparagine; – = matrix and hemagglutinin gene PCR negative; (NA) = HA sequencing unsuccessful.