It was surprising that subject 85 was infected and reporting flu-like symptoms with a virus encoding the T64-NS1 protein (see Table S5 in the supplemental material), as we have shown that this mutation is quite rare in the human population (0.03%), most probably because this virus is highly sensitive to IFN responses and is highly attenuated, at least in mice (Fig. 8). The gene discussed is IFNA1; the disease is influenza.