Content area
Full Text
About the Authors:
Srinivas S. Rao
Affiliation: Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, Maryland, United States of America
Wing-Pui Kong
Affiliation: Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, Maryland, United States of America
Chih-Jen Wei
Affiliation: Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, Maryland, United States of America
Neal Van Hoeven
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
J. Patrick Gorres
Affiliation: Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, Maryland, United States of America
Martha Nason
Affiliation: Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, Maryland, United States of America
Hanne Andersen
Affiliation: BIOQUAL, Inc., Rockville, Maryland, United States of America
Terrence M. Tumpey
Affiliation: Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
Gary J. Nabel
* E-mail: [email protected]
Affiliation: Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, Maryland, United States of America
Introduction
Since 1997, the highly pathogenic avian influenza A H5N1 viral strain has caused severe disease in poultry and wild birds. Although H5N1 has not spread widely in humans, sporadic infections have been seen throughout countries of eastern Asia, the Middle East and Africa. To date, there have been more than 445 confirmed human cases of H5N1, with 263 deaths (59% mortality rate) reported by the World Health Organization (http://www.who.int/csr/disease/avian_influenza/country/cases_table_2009_12_11/en/index.html). In almost all cases, those infected with H5N1 had physical contact with infected birds. While the primary mode of transmission may be animal-to-human, the concern remains that this virus may evolve into a strain capable of human-to-human transmission. Vaccination offers a practical and effective measure for controlling the spread of this highly pathogenic virus. The threat posed by emerging strains of influenza is unpredictable and varies among countries, as evidenced by the recent swine origin H1N1 pandemic, highlighting the need for improved vaccines that can confer broad protection against multiple viral strains and various influenza A subtypes.
While the hemagglutinin (HA) surface protein is conventionally...