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Frequent Genetic Mismatch between Vaccine Strains and Circulating Seasonal Influenza Viruses, Hong Kong, China, 1996–2012

Martin C.W. Chan, Maggie H. Wang, Zigui Chen, David S.C. Hui, Angela K. Kwok, Apple C.M. Yeung, Kun M. Liu, Yun Kit Yeoh, Nelson Lee¹, and Paul K.S. Chan

Author affiliations: Author affiliation: The Chinese University of Hong Kong, Hong Kong, China

Main Article

Proportion of circulating influenza viruses with HA amino acid sequences closely matched with vaccine strains, Hong Kong, China, 1996–2012*

Year, season	Influenza A(H3N2) vaccine strains, %†		Influenza B vaccine strains, %†
Year, season	Northern Hemisphere	Southern Hemisphere	Northern Hemisphere	Southern Hemisphere
1996
Winter	None‡	None‡	All§	All§
Summer	None‡	None‡	77.8	77.8
1997
Winter	All§	None‡	14.7	None‡
Summer	94.4	94.4	None‡	None‡
1998
Winter	None‡	None‡	None‡	None‡
Summer	None‡	None‡	None‡	None‡
1999
Winter	18.8	None‡	6.3	6.3
Summer	None‡	None‡	None‡	None‡
2000
Winter	None‡	None‡	None‡	None‡
Summer	None‡	None‡	None‡	None‡
2001
Winter	All§¶	None‡	None‡	None‡
Summer	84.6¶	84.6¶	None‡	25.0
2002
Winter	41.2¶	41.2¶	None‡	None‡
Summer	6.7	6.7	12.5	12.5
2003
Winter	None‡	None‡	73.3	6.7
Summer	None‡	None‡	None‡	None‡
2004
Winter	None‡	None‡	None‡	None‡
Summer	None‡	None‡	None‡	None‡
2005
Winter	31.3#	None‡	29.4	None‡
Summer	None‡	None‡	12.5	12.5
2006
Winter	None‡	None‡	None‡	None‡
Summer	None‡	None‡	None‡	90.0
2007
Winter	52.4	None‡	9.1	9.1
Summer	6.7	6.7	None‡	None‡
2008
Winter	None‡	None‡	22.2	22.2
Summer	None‡	All§	None‡	None‡
2009
Winter	52.2	52.2	None‡	None‡
Summer**	22.2	22.2	None‡	None‡
2010
Winter	None‡	None‡	66.7	None‡
Summer	None‡	92.9	26.7	26.7
2011
Winter	87.5	87.5	64.3	64.3
Summer	None‡	None‡	37.5	37.5
2012
Winter	None‡	None‡	31.0	31.0
Summer	None‡	None‡	None‡	None‡

*Calendar months belonging to winter or summer influenza seasons were based on the average number of cases admitted per month during the study period (Figure 1). Winter seasons were November of previous year through April of current year; influenza usually peaks in February and March. Summer seasons were May–October; influenza usually peaks in July and August. HA, hemagglutinin.
†Co-circulation of multiple strains with a certain percentage closely matched the contemporary vaccine strain based on HA amino acid sequence comparison.
‡None of the circulating viruses examined were closely matched with the contemporary vaccine strain based on HA amino acid sequence comparison.
§All circulating viruses examined were closely matched with the contemporary vaccine strain based on HA amino acid sequence comparison.
¶A/Panama/1999, an alternate to A/Moscow/99, closely matched the circulating strains of 2001 winter and summer seasons and 2002 winter season.
#The World Health Organization recommended 2 A(H3N2) vaccine strains for the Northern Hemisphere in 2005, one of which, A/Wyoming/2003, closely matched a portion of the viruses circulating during the 2005 winter season.
**Dominated by influenza A(H1N1)pdm09.

Main Article

¹Current affiliation: University of Alberta, Edmonton, Alberta, Canada.

Page created: September 16, 2018

Page updated: September 16, 2018

Page reviewed: September 16, 2018

The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.

Volume 24, Number 10—October 2018

Research

Frequent Genetic Mismatch between Vaccine Strains and Circulating Seasonal Influenza Viruses, Hong Kong, China, 1996–2012

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