tetano
Editor, Senior Moderator
Oxford Journals
Medicine
Clinical Infectious Diseases
Advance Access
10.1093/cid/cis885
Influenza B lineage circulation and hospitalisation rate in a subtropical city, Hong Kong, 2000-2010
Paul K. S. Chan1,2,*,
Martin C. W. Chan1,
Jo L. K. Cheung1,
Nelson Lee2,3,
Ting F. Leung4,
Apple C. M. Yeung1,
Martin C. S. Wong5,
Karry L. K. Ngai1,
E Anthony S. Nelson4, and
David S. C. Hui2,3
+ Author Affiliations
1Department of Microbiology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
3Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
4Department of Paediatrics; The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
2Department of Paediatrics; and Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
5Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
↵*Correspondence to: Prof. Paul KS Chan, Department of Microbiology, Faculty of Medicine, The Chinese University of Hong Kong, 1/F Clinical Sciences Building, Prince of Wales Hospital, Shatin, New Territories, Hong Kong Special Administrative Region, People?s Republic of China. E-mail: paulkschan@cuhk.edu.hk, Tel: (852) 2632 3333, Fax: (852) 2647 3227
Abstract
Background. A need for quadrivalent vaccines to cover both lineages of influenza B has been raised. Information on the circulation status of influenza B lineages, and the associated hospitalisation rates is important to assist evidence-based decision making. This retrospective study revealed the situation in a subtropical city over a 10-year period.
Methods. Sequences of 268 influenza B isolates were analyzed to identify the circulating pool of virus lineages for each year. Hospital records and population census data were used to estimate annual age-specific hospitalisation rates.
Results. Co-circulation with two influenza B lineages was found in 9 of the 10 years. Only in 6 of the 10 years had the vaccine strain successfully matched with the lineage that was found in >50% of the circulating pool. Six years were predominated by one lineage (occupying >80% of the circulating pool), and these years had higher (average, 1.4-fold) hospitalisation rates. Matching between vaccine and circulating lineage was achieved only in 2 of the 6 ?predominated years?. The Yamagata lineage accounted for most (5/6) of the ?predominated years?. Overall, 24% of influenza admissions were due to influenza B, and influenza B contributed to a higher proportion (41.9%) among children and young teenagers (5-14 years old).
Conclusions. Co-circulation with two influenza B lineages is common in the subtropical region. To predict the next predominant lineage proves to be difficult. Influenza B accounts for a substantial fraction of influenza-associated hospitalisations, especially among children and young teenagers. Quadrivalent vaccines may improve the effectiveness of influenza vaccination programs.
http://cid.oxfordjournals.org/content/early/2012/10/10/cid.cis885.abstract
Medicine
Clinical Infectious Diseases
Advance Access
10.1093/cid/cis885
Influenza B lineage circulation and hospitalisation rate in a subtropical city, Hong Kong, 2000-2010
Paul K. S. Chan1,2,*,
Martin C. W. Chan1,
Jo L. K. Cheung1,
Nelson Lee2,3,
Ting F. Leung4,
Apple C. M. Yeung1,
Martin C. S. Wong5,
Karry L. K. Ngai1,
E Anthony S. Nelson4, and
David S. C. Hui2,3
+ Author Affiliations
1Department of Microbiology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
3Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
4Department of Paediatrics; The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
2Department of Paediatrics; and Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
5Jockey Club School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
↵*Correspondence to: Prof. Paul KS Chan, Department of Microbiology, Faculty of Medicine, The Chinese University of Hong Kong, 1/F Clinical Sciences Building, Prince of Wales Hospital, Shatin, New Territories, Hong Kong Special Administrative Region, People?s Republic of China. E-mail: paulkschan@cuhk.edu.hk, Tel: (852) 2632 3333, Fax: (852) 2647 3227
Abstract
Background. A need for quadrivalent vaccines to cover both lineages of influenza B has been raised. Information on the circulation status of influenza B lineages, and the associated hospitalisation rates is important to assist evidence-based decision making. This retrospective study revealed the situation in a subtropical city over a 10-year period.
Methods. Sequences of 268 influenza B isolates were analyzed to identify the circulating pool of virus lineages for each year. Hospital records and population census data were used to estimate annual age-specific hospitalisation rates.
Results. Co-circulation with two influenza B lineages was found in 9 of the 10 years. Only in 6 of the 10 years had the vaccine strain successfully matched with the lineage that was found in >50% of the circulating pool. Six years were predominated by one lineage (occupying >80% of the circulating pool), and these years had higher (average, 1.4-fold) hospitalisation rates. Matching between vaccine and circulating lineage was achieved only in 2 of the 6 ?predominated years?. The Yamagata lineage accounted for most (5/6) of the ?predominated years?. Overall, 24% of influenza admissions were due to influenza B, and influenza B contributed to a higher proportion (41.9%) among children and young teenagers (5-14 years old).
Conclusions. Co-circulation with two influenza B lineages is common in the subtropical region. To predict the next predominant lineage proves to be difficult. Influenza B accounts for a substantial fraction of influenza-associated hospitalisations, especially among children and young teenagers. Quadrivalent vaccines may improve the effectiveness of influenza vaccination programs.
http://cid.oxfordjournals.org/content/early/2012/10/10/cid.cis885.abstract