260551 Outbreak of influenza A H3N2 and influenza B virus mixed infection post-mass vaccination during 2009-2010 in central Taiwan

Monday, October 29, 2012

Yu-Ching Lan, PhD , Department of Health Risk Management, China Medical University, Taichung, Taiwan
Chi-Jung Hsin , Department of Public Health, China Medical University, Taichung, Taiwan
Ting-Wei Chi , Department of Public Health, China Medical University,Taiwan, Taichung, Taiwan
Yi-Chen Yang , Department of health risk management, China Medical University, Taichung, Taiwan
Background: A pandemic outbreak of the A/H1N1 swine-origin influenza virus occurred in 2009. In response, Taiwan authorities approved a national vaccination program at the end of 2009.To investigate their vaccination effect after the end of 2009, non-H1N1 influenza epidemic, and transmission relationships were investigated in Taiwan. Methods : Patients with specific respiratory symptoms were recruited from a university hospital in central Taiwan. Respiratory tract specimens were analyzed using rapid diagnostic influenza A & B tests and virus subtyping. A phylogenetic analysis was performed to clarify transmission relationships. Finding: A neighbor-joining phylogenetic tree constructed from the 92 influenza A H3N2 and 75 influenza B sequences in Taiwan central that were the focus of this study. In the H3N2 tree , all central Taiwan cases belong to a large clade that also contains the A/Perth/2009/CY081428.1 vaccine strain under statistic. According to results from a neighbor-joining analysis, 14/18 Taiwan H3N2 sequences separated into 3 major monophyletic clusters with statistical significance. According to the influenza B neighbor-joining tree, all 14 sequences displayed 3 monophyletic clusters. In terms of HA sequences, 12 strains were Victoria-like and 2 Yamagata-like. Note the central Taiwan founder clusters of influenza A H3N2 and influenza B outbreaks following the late-2009 H1 vaccination program. Conclusions: According to our phylogenetic data, at least 11 independent introductions of influenza A and B viruses continue to sustain transmission in central Taiwan.

Learning Areas:
Epidemiology
Public health biology

Learning Objectives:
To demonstrate their vaccination effect after the end of 2009, non-H1N1 influenza epidemic, and transmission relationships were investigated in Taiwan.

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I have been the principal of multiple Taiwan NSC funded grants focusing on the molecular epidemiology of virus, HIV prevention, and drug user. Among my scientific interests has been the research for evolution of virus transmission.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.