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Paper of the Month April 2012

Cold-Adapted Pandemic 2009 H1N1 Influenza Virus Live Vaccine Elicits Cross- Reactive Immune Responses against Seasonal and H5 Influenza A Viruses

J Virol. 2012 Mar 21 [Epub ahead of print] PMID: 22438541


Yo Han Jang, Young Ho Byun, Yoon Jae Lee, Yun Ha Lee, Kwang-Hee Lee, and Baik Lin Seong


The global transmission of the pandemic 2009 H1N1 influenza virus (pdmH1N1) among humans raised a serious concern for the potential emergence of genetic reassortant between the pdmH1N1 and other highly pathogenic influenza strains, especially the avian H5N1 influenza virus, geared to high mortality and rapid transmission. Vaccination remains the most rational and practical approach for the pandemic preparedness. We reported that the cold-adapted X-31 live attenuated pdmH1N1 vaccine (CApH1N1) elicits cross-reactive immunity to seasonal human influenza and avian H5 influenza viruses in the mouse model. The vaccination induced both systemic and mucosal antibodies with broad reactivity to seasonal and H5 strains including HPAI H5N1 and the avian H5N2 virus, providing complete protection against heterologous and hetero-subtypic lethal challenges by single immunization. The results further extend previous reports on the merit of using live attenuated influenza vaccine for cross-protection. While addressing to the biosecurity concerns associated with the lab-made mammalian-transmissible highly pathogenic H5N1 influenza viruses, the live vaccine shows its potential for mitigating the severity of infections with natural reassortants between pdmH1N1 and highly pathogenic H5 subtype viruses.