Epidemiology and Infection

Original Papers

Vaccination

Age-specific vaccine effectiveness of seasonal 2010/2011 and pandemic influenza A(H1N1) 2009 vaccines in preventing influenza in the United Kingdom

R. G. PEBODYa1 c1, N. ANDREWSa1, D. M. FLEMINGa2, J. McMENAMINa3, S. COTTRELLa4, B. SMYTHa5, H. DURNALLa2, C. ROBERTSONa3a6a9, W. CARMANa7, J. ELLISa8, P. SEBASTIAN-PILLAIa8, M. ZAMBONa8, C. KEARNSa5, C. MOOREa4, D. RH. THOMASa4 and J. M. WATSONa1

a1 Health Protection Agency Health Protection Services – Colindale, London, UK

a2 Royal College of General Practitioners Research and Surveillance Centre, Birmingham, UK

a3 Health Protection Scotland, Glasgow, UK

a4 Public Health Wales, Cardiff, UK

a5 Public Health Agency Northern Ireland, Belfast, UK

a6 University of Strathclyde, Glasgow, UK

a7 West of Scotland Specialist Virology Centre, Glasgow, UK

a8 Health Protection Agency Microbiology Services – Colindale, London, UK

a9 International Prevention Research Institute, Lyon, France

SUMMARY

An analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI −6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group.

(Received February 03 2012)

(Revised May 02 2012)

(Accepted May 15 2012)

(Online publication June 13 2012)

Key words

  • Influenza;
  • influenza vaccines;
  • vaccine-preventable diseases

Correspondence:

c1 Author for correspondence: Dr R. G. Pebody, Health Protection Services – Colindale, Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, UK. (Email: Richard.Pebody@hpa.org.uk)

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