Seasonal influenza vaccine effectiveness in people with asthma: a national test-negative design case-control study

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Clin Infect Dis. 2019 Nov 5. pii: ciz1086. doi: 10.1093/cid/ciz1086. [Epub ahead of print] Seasonal influenza vaccine effectiveness in people with asthma: a national test-negative design case-control study.

Vasileiou E, Sheikh A¹, Butler CC², Robertson C³, Kavanagh K⁴, Englishby T⁴, Lone NI¹, von Wissmann B⁵, McMenamin J⁵, Ritchie LD⁶, Schwarze J⁷, Gunson R⁸, Simpson CR⁹.
Author information

1 Asthma UK Centre for Applied Research, Usher Institute, The University of Edinburgh, Edinburgh, UK. 2 Nuffield Department of Primary Care Health Sciences, Oxford University, New Radcliffe House, Radcliffe Observatory Quarter, Woodstock Road, Oxford, UK and Cardiff University, Institute of Primary Care and Public Health, Cardiff, UK. 3 Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK and Health Protection Scotland, Glasgow, UK. 4 Department of Mathematics and Statistics, University of Strathclyde, Glasgow, UK. 5 Health Protection Scotland, NHS National Services Scotland, Meridian Court, Glasgow, UK. 6 Centre of Academic Primary Care, University of Aberdeen, Aberdeen, UK. 7 Centre for Inflammation Research, Queen's Medical Research Institute, Child Life and Health, The University of Edinburgh, Edinburgh, UK. 8 West of Scotland Specialist Virology Centre, Glasgow, UK. 9 School of Health, Faculty of Health, Victoria University of Wellington, Wellington, New Zealand and Asthma UK Centre for Applied Research, Usher Institute, The University of Edinburgh, Edinburgh, UK.

Abstract

BACKGROUND:

Influenza infection is an important trigger of asthma attacks. Influenza vaccination has the potential to reduce the incidence of influenza in people with asthma, but uptake remains persistently low, partially reflecting concerns about vaccine effectiveness (VE).
METHODS:

We conducted a test-negative design case-control study to estimate the effectiveness of influenza vaccine in children and adults with asthma in Scotland over six influenza seasons (2010/11 to 2015/16). We used individual patient level data from 223 primary care practices which yielded 1,830,772 patient-years of data, which were linked with hospital and virological (n=5,910 swabs) data.
RESULTS:

Vaccination was associated with an overall 55.0% (95% confidence interval (CI): 45.8-62.7) reduction in the risk of a laboratory-confirmed influenza infection in people with asthma over the six seasons. There was substantial variation in VE between seasons, influenza strains and age groups. The highest VE (76.1%; 95% CI: 55.6-87.1) was found in 2010/11 season where the A(H1N1) strain dominated and there was a good antigenic vaccine match. High protection was observed against A(H1N1) (e.g. 2010/11: 70.7%; 95%CI: 32.5-87.3) and B strains (e.g. 2010/11: 83.2%; 95%CI: 44.3-94.9), but there was lower protection for the A(H3N2) strain (e.g. 2014/15: 26.4%; 95%CI: -12.0-51.6). The highest VE against all viral strains was observed in adults aged 18-54 years (57.0%; 95%CI: 42.3-68.0).
CONCLUSION:

Influenza vaccination gave meaningful protection against laboratory-confirmed influenza in people asthma across all six seasons. Strategies to boost influenza vaccine uptake has the potential to substantially reduce influenza triggered asthma attacks.
? The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America.


KEYWORDS:

asthma; influenza; laboratory confirmed influenza; vaccination

PMID: 31688921 DOI: 10.1093/cid/ciz1086