Asymptomatic Influenza A(H5N1) Infections and Sustained Surveillance—Sustaining Surveillance Beyond the Crisis

Dawood and colleagues1 provide an important insight into influenza A(H5N1) infections and the surveillance tools needed for pandemic preparedness. Through rigorous review of international literature and careful molecular and serologic confirmation in 16 cases outside of the US, the authors document that influenza A(H5N1) infections among humans do not always present with severe illness, that asymptomatic infections occur, and in some settings, there is probable person-to-person transmission. This finding challenges the traditional perception that influenza A(H5N1) infection among humans is almost invariably symptomatic and severe.