Asymptomatic, mild, and severe influenza A(H7N9) virus infection in humans, Guangzhou, China

Abstract

Targeted surveillance for influenza A(H7N9) identified 21 cases of infection with this virus in Guangzhou, China, during April 1, 2013-March 7, 2014. The spectrum of illness ranged from severe pneumonia to asymptomatic infection. Epidemiologic findings for a family cluster of 1 severe and 1 mild case suggested limited person-to-person transmission of this virus.