Yat Hung Tam1, Sophie A Valkenburg2, Ranawaka A P M Perera1,3, Jennifer H F Wong1, Vicky J Fang1, Tiffany W Y Ng1, Alfred S K Kwong4, Wendy W S Tsui4, Dennis K M Ip1, Leo L M Poon1,3, Chris K V Chau4, Ian G Barr5,6, Joseph S Malik Peiris1,3, Benjamin J Cowling1. 1. World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, China. 2. HKU-Pasteur Research Pole, School of Public Health, China. 3. Centre for Influenza Research, Li Ka Shing Faculty of Medicine, University of Hong Kong, China. 4. Department of Family Medicine and Primary Healthcare, Queen Mary Hospital, Hospital Authority, Hong Kong Special Administrative Region, China. 5. World Health Organization Collaborating Centre for Reference and Research. 6. Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia.
Abstract
Background: Many health authorities recommend influenza vaccination of older adults to reduce disease burden. We hypothesized that in tropical and subtropical areas with more prolonged influenza seasons, twice-annual influenza vaccination might provide older adults with improved immunity against influenza. Methods: In 2014-2015, Hong Kong experienced a substantial A(H3N2) winter epidemic with a mismatched vaccine. Local authorities procured and administered to older adults the 2015 southern hemisphere influenza vaccine, which included an updated and matching A/Switzerland/9715293/2013(H3N2) strain. We compared immune parameters in pre- and postvaccination sera from older adults ≥75 years of age who received 1 vs 2 influenza vaccines per year. Results: We enrolled 978 older adults with 470 vaccinations for summer 2015 and 827 vaccinations for winter 2015-2016. Recipients of southern hemisphere vaccination had higher geometric mean titers (GMTs) by the hemagglutination inhibition assay against all 3 vaccine strains. When receiving influenza vaccination for the subsequent winter, the southern hemisphere vaccine recipients had higher prevaccination GMTs but lower postvaccination GMTs, compared to those who had not received the southern hemisphere vaccine. Furthermore, cellular immunity was impacted by biannual vaccination, with reduced influenza-specific CD4 T-cell responses in the second season of vaccination. Conclusions: We observed some reductions in immune responses in the twice-annual vaccination group compared with the once-annual vaccination group, in the context of unchanging vaccine strains, while protection was likely to have been improved during the summer and autumn for the twice-annual vaccination group due to the continued circulation of the A/Switzerland/9715293/2013(H3N2) virus.
Background: Many health authorities recommend influenza vaccination of older adults to reduce disease burden. We hypothesized that in tropical and subtropical areas with more prolonged influenza seasons, twice-annual influenza vaccination might provide older adults with improved immunity against influenza. Methods: In 2014-2015, Hong Kong experienced a substantial A(H3N2) winter epidemic with a mismatched vaccine. Local authorities procured and administered to older adults the 2015 southern hemisphere influenza vaccine, which included an updated and matching A/Switzerland/9715293/2013(H3N2) strain. We compared immune parameters in pre- and postvaccination sera from older adults ≥75 years of age who received 1 vs 2 influenza vaccines per year. Results: We enrolled 978 older adults with 470 vaccinations for summer 2015 and 827 vaccinations for winter 2015-2016. Recipients of southern hemisphere vaccination had higher geometric mean titers (GMTs) by the hemagglutination inhibition assay against all 3 vaccine strains. When receiving influenza vaccination for the subsequent winter, the southern hemisphere vaccine recipients had higher prevaccination GMTs but lower postvaccination GMTs, compared to those who had not received the southern hemisphere vaccine. Furthermore, cellular immunity was impacted by biannual vaccination, with reduced influenza-specific CD4 T-cell responses in the second season of vaccination. Conclusions: We observed some reductions in immune responses in the twice-annual vaccination group compared with the once-annual vaccination group, in the context of unchanging vaccine strains, while protection was likely to have been improved during the summer and autumn for the twice-annual vaccination group due to the continued circulation of the A/Switzerland/9715293/2013(H3N2) virus.
Authors: Benjamin J Cowling; Ranawaka A P M Perera; Sophie A Valkenburg; Nancy H L Leung; A Danielle Iuliano; Yat Hung Tam; Jennifer H F Wong; Vicky J Fang; Athena P Y Li; Hau Chi So; Dennis K M Ip; Eduardo Azziz-Baumgartner; Alicia M Fry; Min Z Levine; Shivaprakash Gangappa; Suryaprakash Sambhara; Ian G Barr; Danuta M Skowronski; J S Malik Peiris; Mark G Thompson Journal: Clin Infect Dis Date: 2020-10-23 Impact factor: 9.079
Authors: Benjamin J Cowling; Celine S L Chui; Wey Wen Lim; Peng Wu; Christopher K M Hui; J S Malik Peiris; Esther W Chan Journal: PLoS One Date: 2018-01-19 Impact factor: 3.240
Authors: Sophie A Valkenburg; Vicky J Fang; Nancy Hl Leung; Daniel Kw Chu; Dennis Km Ip; Ranawaka Apm Perera; Yizhuo Wang; Athena Py Li; Js Malik Peiris; Benjamin J Cowling; Leo Lm Poon Journal: Clin Transl Immunology Date: 2019-11-20
Authors: 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 Lee; Paul K S Chan Journal: Emerg Infect Dis Date: 2018-10 Impact factor: 6.883