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Using a test-negative design, the Canadian Sentinel Practitioner Surveillance Network (SPSN) assessed interim 2015/16 vaccine effectiveness (VE) against influenza A(H1N1)pdm09 viruses. Adjusted VE showed significant protection of 64% (95% confidence interval (CI): 44–77%) overall and 56% (95%CI: 26–73%) for adults between 20 and 64 years-old against medically attended, laboratory-confirmed A(H1N1)pdm09 illness. Among the 67 A(H1N1)pdm09-positive specimens that were successfully sequenced, 62 (> 90%) belonged to the emerging genetic 6B.1 subclade, defined by S162N (potential gain of glycosylation) and I216T mutations in the haemagglutinin protein. Findings from the Canadian SPSN indicate that the 2015/16 northern hemisphere vaccine provided significant protection against A(H1N1)pdm09 illness despite genetic evolution in circulating viruses.


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  1. Appiah GD, Blanton L, D’Mello T, Kniss K, Smith S, Mustaquim D, et al. Centers for Disease Control and Prevention (CDC). Influenza activity - United States, 2014-15 season and composition of the 2015-16 influenza vaccine. MMWR Morb Mortal Wkly Rep. 2015;64(21):583-90. PMID: 26042650 
  2. Public Health Agency of Canada (PHAC). FluWatch report: August 16 to August 29, 2015 (weeks 33 & 34). Ottawa: PHAC; 2016. [Accessed: 16 Feb 2016]. Available from: http://www.phac-aspc.gc.ca/fluwatch/14-15/index-eng.php
  3. Public Health Agency of Canada (PHAC). FluWatch report: February 28, 2016 – March 5, 2016 (week 09). Ottawa: PHAC; 2016. [Accessed: 14 Mar 2016]. Available from: http://healthycanadians.gc.ca/diseases-conditions-maladies-affections/disease-maladie/flu-grippe/surveillance/reports-season-2015-2016-saison-rapports-eng.php
  4. Russell K, Blanton L, Kniss K, Mustaquim D, Smith S, Cohen J, et al. Update: influenza activity – United States, October 4, 2015-February 6, 2016. MMWR Morb Mortal Wkly Rep. 2016;65(6):146-53.  https://doi.org/10.15585/mmwr.mm6506a3  PMID: 26891596 
  5. World Health Organization (WHO). Risk assessment - seasonal influenza A(H1N1)pdm09. Geneva: WHO; 2016. Available from: http://www.who.int/influenza/publications/riskassessment_AH1N1pdm09_201602/en/
  6. European Centre for Disease Prevention and Control (ECDC). Influenza virus characterization, summary Europe, February 2016. Stockholm: ECDC; 2016. Available from: http://ecdc.europa.eu/en/publications/Publications/influenza-virus-characterisation-february-2016.pdf
  7. World Health Organization (WHO). Recommended composition of influenza virus vaccines for use in the 2016-2017 northern hemisphere influenza season. Geneva: WHO; 2016. Available from: http://www.who.int/influenza/vaccines/virus/recommendations/2016_17_north/en/
  8. Kissling E, Valenciano M. Early influenza vaccine effectiveness results 2015-16: I-MOVE multicentre case-control study. Euro Surveill. 2016;21(6):30134.  https://doi.org/10.2807/1560-7917.ES.2016.21.6.30134  PMID: 26898240 
  9. World Health Organization (WHO). Recommended composition of influenza virus vaccines for use in the 2015-2016 northern hemisphere influenza season. Geneva: WHO; 2015. Available from: http://www.who.int/influenza/vaccines/virus/recommendations/2015_16_north/en/
  10. World Health Organization (WHO). Recommended viruses for influenza vaccines for use in the 2010-2011 northern hemisphere influenza season. Geneva: WHO; 2010. Available from: http://www.who.int/influenza/vaccines/virus/2010_11north/en/
  11. Brownlee GG, Fodor E. The predicted antigenicity of the haemagglutinin of the 1918 Spanish influenza pandemic suggests an avian origin. Philos Trans R Soc Lond B Biol Sci. 2001;356(1416):1871-6.  https://doi.org/10.1098/rstb.2001.1001  PMID: 11779386 
  12. Skowronski DM, Chambers C, Sabaiduc S, De Serres G, Winter AL, Dickinson JA, et al. Integrated sentinel surveillance linking genetic, antigenic, and epidemiologic monitoring of influenza vaccine-virus relatedness and effectiveness during the 2013-2014 influenza season. J Infect Dis. 2015;212(5):726-39.  https://doi.org/10.1093/infdis/jiv177  PMID: 25784728 
  13. Skowronski D, Chambers C, Sabaiduc S, De Serres G, Dickinson J, Winter A, et al. Interim estimates of 2013/14 vaccine effectiveness against influenza A(H1N1)pdm09 from Canada s sentinel surveillance network, January 2014. Euro Surveill. 2014;19(5):20690.  https://doi.org/10.2807/1560-7917.ES2014.19.5.20690  PMID: 24524234 
  14. Skowronski DM, Chambers C, Sabaiduc S, De Serres G, Dickinson JA, Winter AL, et al. Interim estimates of 2014/15 vaccine effectiveness against influenza A(H3N2) from Canada’s Sentinel Physician Surveillance Network, January 2015. Euro Surveill. 2015;20(4):21022.  https://doi.org/10.2807/1560-7917.ES2015.20.4.21022  PMID: 25655053 
  15. Skowronski DM, Janjua NZ, De Serres G, Hottes TS, Dickinson JA, Crowcroft N, et al. Effectiveness of AS03 adjuvanted pandemic H1N1 vaccine: case-control evaluation based on sentinel surveillance system in Canada, autumn 2009. BMJ. 2011;342(feb03 1):c7297.
  16. Belongia EA, Simpson MD, King JP, Sundaram ME, Kelley NS, Osterholm MT, et al. Variable influenza vaccine effectiveness by subtype: a meta-analysis of test negative design studies. Lancet Infect Dis. 2016; (Forthcoming).
  17. Valenciano M, Kissling E, Reuss A, Jiménez-Jorge S, Horváth JK, Donnell JM, et al. I-MOVE Multicentre Case Control Study Team. The European I-MOVE Multicentre 2013-2014 Case-Control Study. Homogeneous moderate influenza vaccine effectiveness against A(H1N1)pdm09 and heterogenous results by country against A(H3N2). Vaccine. 2015;33(24):2813-22.  https://doi.org/10.1016/j.vaccine.2015.04.012  PMID: 25936723 
  18. Valenciano M, Kissling E, Reuss A, Rizzo C, Gherasim A, Horváth JK, et al. Joan O´DonellI-MOVE multicentre case–control team. Vaccine effectiveness in preventing laboratory-confirmed influenza in primary care patients in a season of co-circulation of influenza A(H1N1)pdm09, B and drifted A(H3N2), I-MOVE Multicentre Case-Control Study, Europe 2014/15. Euro Surveill. 2016;21(7):30139.  https://doi.org/10.2807/1560-7917.ES.2016.21.7.30139  PMID: 26924024 
  19. US Centers for Disease Control and Prevention (CDC). Flu vaccine nearly 60 percent effective. Atlanta: US CDC; 2016. [Accessed: 25 Feb 2016]. Available from: http://www.cdc.gov/media/releases/2016/flu-vaccine-60-percent.html
  20. Gaglani M, Pruszynski J, Murthy K, Clipper L, Robertson A, Reis M, et al. Influenza vaccine effectiveness against 2009 pandemic influenza A(H1N1) virus differed by vaccine type during 2013-2014 in the United States. J Infect Dis. 2016;jiv577. [Epub ahead of print].
  21. Linderman SL, Chambers BS, Zost SJ, Parkhouse K, Li Y, Herrmann C, et al. Potential antigenic explanation for atypical H1N1 infections among middle-aged adults during the 2013-2014 influenza season. Proc Natl Acad Sci USA. 2014;111(44):15798-803.  https://doi.org/10.1073/pnas.1409171111  PMID: 25331901 
  22. Igarashi M, Ito K, Yoshida R, Tomabechi D, Kida H, Takada A. Predicting the antigenic structure of the pandemic (H1N1) 2009 influenza virus hemagglutinin. PLoS One. 2010;5(1):e8553.  https://doi.org/10.1371/journal.pone.0008553  PMID: 20049332 
  23. Tate MD, Job ER, Deng YM, Gunalan V, Maurer-Stroh S, Reading PC. Playing hide and seek: how glycosylation of the influenza virus hemagglutinin can modulate the immune response to infection. Viruses. 2014;6(3):1294-316.  https://doi.org/10.3390/v6031294  PMID: 24638204 
  24. World Health Organization (WHO). Questions and answers – recommended composition of influenza virus vaccines for use in the northern hemisphere 2016-2017 influenza season and development of candidate vaccines for pandemic preparedness. Geneva: WHO; 2016. Available from: http://www.who.int/influenza/vaccines/virus/recommendations/201602_qanda_recommendation.pdf?ua=1
  25. De Serres G, Skowronski DM, Wu XW, Ambrose CS. The test-negative design: validity, accuracy and precision of vaccine efficacy estimates compared to the gold standard of randomised placebo-controlled clinical trials. Euro Surveill. 2013;18(37):20585.  https://doi.org/10.2807/1560-7917.ES2013.18.37.20585  PMID: 24079398 
  26. Foppa IM, Haber M, Ferdinands JM, Shay DK. The case test-negative design for studies of the effectiveness of influenza vaccine. Vaccine. 2013;31(30):3104-9.  https://doi.org/10.1016/j.vaccine.2013.04.026  PMID: 23624093 
  27. Jackson ML, Nelson JC. The test-negative design for estimating influenza vaccine effectiveness. Vaccine. 2013;31(17):2165-8.  https://doi.org/10.1016/j.vaccine.2013.02.053  PMID: 23499601 
  28. Feng S, Cowling BJ, Sullivan SG. Influenza vaccine effectiveness by test-negative design - Comparison of inpatient and outpatient settings. Vaccine. 2016;34(14):1672-9.  https://doi.org/10.1016/j.vaccine.2016.02.039  PMID: 26920469 
  29. National Advisory Committee on Immunization (NACI). Statement on seasonal influenza vaccine for 2015-2016. Ottawa: NACI; 2015. Available from: http://www.phac-aspc.gc.ca/naci-ccni/flu-2015-grippe-eng.php

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