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PLoS Med. Association between the 2008?09 Seasonal Influenza Vaccine and Pandemic H1N1 Illness during Spring?Summer 2009: Four Observational Studies from Canada.
Association between the 2008?09 Seasonal Influenza Vaccine and Pandemic H1N1 Illness during Spring?Summer 2009: Four Observational Studies from Canada (PLOS, abstract, edited)
[Source: PLoS Medicine, Full PDF Document (LINK). Edited.]
Association between the 2008?09 Seasonal Influenza Vaccine and Pandemic H1N1 Illness during Spring?Summer 2009: Four Observational Studies from Canada
In three case-control studies and a household transmission cohort, Danuta Skowronski and colleagues find an association between prior seasonal flu vaccination and increased risk of 2009 pandemic H1N1 flu.
Danuta M. Skowronski 1*, Gaston De Serres 2, Natasha S. Crowcroft 3,4, Naveed Z. Janjua 1, Nicole Boulianne 2, Travis S. Hottes 1, Laura C. Rosella 3,4, James A. Dickinson 5, Rodica Gilca 2, Pam Sethi 3, Najwa Ouhoummane 2, Donald J. Willison 3, Isabelle Rouleau 2, Martin Petric 1, Kevin Fonseca 6, Steven J. Drews 5, Anuradha Rebbapragada 3, Hugues Charest 2, Marie-?ve Hamelin 7, Guy Boivin 7, Jennifer L. Gardy 1, Yan Li 8, Trijntje L. Kwindt 1, David M. Patrick 1, Robert C. Brunham 1, for the Canadian SAVOIR Team?
1 British Columbia Centre for Disease Control (BCCDC), Vancouver, British Columbia, Canada,
2 Institut national de sant? publique du Qu?bec, Qu?bec, Canada,
3 Ontario Agency for Health Protection and Promotion, Toronto, Ontario, Canada,
4 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada,
5 University of Calgary, Calgary, Alberta, Canada,
6 Alberta Provincial Laboratory, Alberta, Canada,
7 Centre Hospitalier Universitaire de Qu?bec (CHUQ) Research Center, Laval University, Qu?bec, Canada,
8 National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
Abstract
Background
In late spring 2009, concern was raised in Canada that prior vaccination with the 2008?09 trivalent inactivated influenza vaccine (TIV) was associated with increased risk of pandemic influenza A (H1N1) (pH1N1) illness. Several epidemiologic investigations were conducted through the summer to assess this putative association.
Methods and Findings
Studies included: (1) test-negative case-control design based on Canada's sentinel vaccine effectiveness monitoring system in British Columbia, Alberta, Ontario, and Quebec; (2) conventional case-control design using population controls in Quebec; (3) test-negative case-control design in Ontario; and (4) prospective household transmission (cohort) study in Quebec. Logistic regression was used to estimate odds ratios for TIV effect on community- or hospital-based laboratory-confirmed seasonal or pH1N1 influenza cases compared to controls with restriction, stratification, and adjustment for covariates including combinations of age, sex, comorbidity, timeliness of medical visit, prior physician visits, and/or health care worker (HCW) status. For the prospective study risk ratios were computed. Based on the sentinel study of 672 cases and 857 controls, 2008?09 TIV was associated with statistically significant protection against seasonal influenza (odds ratio 0.44, 95% CI 0.33?0.59). In contrast, estimates from the sentinel and three other observational studies, involving a total of 1,226 laboratory-confirmed pH1N1 cases and 1,505 controls, indicated that prior receipt of 2008?09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring?summer 2009, with estimated risk or odds ratios ranging from 1.4 to 2.5. Risk of pH1N1 hospitalization was not further increased among vaccinated people when comparing hospitalized to community cases.
Conclusions
Prior receipt of 2008?09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring?summer 2009 in Canada. The occurrence of bias (selection, information) or confounding cannot be ruled out. Further experimental and epidemiological assessment is warranted. Possible biological mechanisms and immunoepidemiologic implications are considered.
Citation: Skowronski DM, De Serres G, Crowcroft NS, Janjua NZ, Boulianne N, et al. (2010) Association between the 2008?09 Seasonal Influenza Vaccine and Pandemic H1N1 Illness during Spring?Summer 2009: Four Observational Studies from Canada. PLoS Med 7(4): e1000258. doi:10.1371/journal.pmed.1000258
Academic Editor: Lone Simonsen, George Washington University, United States of America
Received: November 2, 2009; Accepted: March 1, 2010; Published: April 6, 2010
Copyright: ? 2010 Skowronski et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This project was funded by the Canadian Institutes of Health Research, the British Columbia Ministry of Health and the British Columbia Centre for Disease Control, Alberta Health and Wellness, the Ontario Agency for Health Protection and Promotion, the Ontario Ministry of Health and Long Term Care, the Minist?re de la sant? et des services sociaux du Qu?bec, the Institut national de sant? publique du Qu?bec and the Fonds de la recherche en sant? du Qu?bec (FRSQ). Although agencies of the investigators provided infrastructure in support of the reported studies, the funders did not have a role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: DMS has previously received research grant funding from GlaxoSmithKline and Sanofi-Pasteur for separate studies. GDS and NB have received research grant funding from GlaxoSmithKline and Sanofi-Pasteur for separate studies. GB has received funding from GlaxoSmithKline for unrelated projects. SAVOIR contributor Allison McGeer has received investigator initiated research grant funding from GlaxoSmithKline, and speaking honoraria from GlaxoSmithKline and Sanofi-Pasteur.
Abbreviations: ADE, antibody-dependent enhancement; BC, British Columbia; CCHS, Canadian Community Health Survey; CI,, confidence interval; HCW, health care worker; ILI, influenza-like illness; NA, neuraminidase; NP, nasopharyngeal; OR, odds ratio; pH1N1, pandemic influenza A (H1N1); RR, risk ratio; SAR, secondary attack rate; SAVOIR, Studies of the Association of Vaccine on Influenza Risk; TIV, trivalent inactivated influenza vaccine; VE, vaccine effectiveness; WHO, World Health Organization
* E-mail: danuta.skowronski@bccdc.ca
? Members of the Canadian SAVOIR Team are listed in the Acknowledgments.
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[Source: PLoS Medicine, Full PDF Document (LINK). Edited.]
Association between the 2008?09 Seasonal Influenza Vaccine and Pandemic H1N1 Illness during Spring?Summer 2009: Four Observational Studies from Canada
In three case-control studies and a household transmission cohort, Danuta Skowronski and colleagues find an association between prior seasonal flu vaccination and increased risk of 2009 pandemic H1N1 flu.
Danuta M. Skowronski 1*, Gaston De Serres 2, Natasha S. Crowcroft 3,4, Naveed Z. Janjua 1, Nicole Boulianne 2, Travis S. Hottes 1, Laura C. Rosella 3,4, James A. Dickinson 5, Rodica Gilca 2, Pam Sethi 3, Najwa Ouhoummane 2, Donald J. Willison 3, Isabelle Rouleau 2, Martin Petric 1, Kevin Fonseca 6, Steven J. Drews 5, Anuradha Rebbapragada 3, Hugues Charest 2, Marie-?ve Hamelin 7, Guy Boivin 7, Jennifer L. Gardy 1, Yan Li 8, Trijntje L. Kwindt 1, David M. Patrick 1, Robert C. Brunham 1, for the Canadian SAVOIR Team?
1 British Columbia Centre for Disease Control (BCCDC), Vancouver, British Columbia, Canada,
2 Institut national de sant? publique du Qu?bec, Qu?bec, Canada,
3 Ontario Agency for Health Protection and Promotion, Toronto, Ontario, Canada,
4 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada,
5 University of Calgary, Calgary, Alberta, Canada,
6 Alberta Provincial Laboratory, Alberta, Canada,
7 Centre Hospitalier Universitaire de Qu?bec (CHUQ) Research Center, Laval University, Qu?bec, Canada,
8 National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
Abstract
Background
In late spring 2009, concern was raised in Canada that prior vaccination with the 2008?09 trivalent inactivated influenza vaccine (TIV) was associated with increased risk of pandemic influenza A (H1N1) (pH1N1) illness. Several epidemiologic investigations were conducted through the summer to assess this putative association.
Methods and Findings
Studies included: (1) test-negative case-control design based on Canada's sentinel vaccine effectiveness monitoring system in British Columbia, Alberta, Ontario, and Quebec; (2) conventional case-control design using population controls in Quebec; (3) test-negative case-control design in Ontario; and (4) prospective household transmission (cohort) study in Quebec. Logistic regression was used to estimate odds ratios for TIV effect on community- or hospital-based laboratory-confirmed seasonal or pH1N1 influenza cases compared to controls with restriction, stratification, and adjustment for covariates including combinations of age, sex, comorbidity, timeliness of medical visit, prior physician visits, and/or health care worker (HCW) status. For the prospective study risk ratios were computed. Based on the sentinel study of 672 cases and 857 controls, 2008?09 TIV was associated with statistically significant protection against seasonal influenza (odds ratio 0.44, 95% CI 0.33?0.59). In contrast, estimates from the sentinel and three other observational studies, involving a total of 1,226 laboratory-confirmed pH1N1 cases and 1,505 controls, indicated that prior receipt of 2008?09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring?summer 2009, with estimated risk or odds ratios ranging from 1.4 to 2.5. Risk of pH1N1 hospitalization was not further increased among vaccinated people when comparing hospitalized to community cases.
Conclusions
Prior receipt of 2008?09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring?summer 2009 in Canada. The occurrence of bias (selection, information) or confounding cannot be ruled out. Further experimental and epidemiological assessment is warranted. Possible biological mechanisms and immunoepidemiologic implications are considered.
Citation: Skowronski DM, De Serres G, Crowcroft NS, Janjua NZ, Boulianne N, et al. (2010) Association between the 2008?09 Seasonal Influenza Vaccine and Pandemic H1N1 Illness during Spring?Summer 2009: Four Observational Studies from Canada. PLoS Med 7(4): e1000258. doi:10.1371/journal.pmed.1000258
Academic Editor: Lone Simonsen, George Washington University, United States of America
Received: November 2, 2009; Accepted: March 1, 2010; Published: April 6, 2010
Copyright: ? 2010 Skowronski et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This project was funded by the Canadian Institutes of Health Research, the British Columbia Ministry of Health and the British Columbia Centre for Disease Control, Alberta Health and Wellness, the Ontario Agency for Health Protection and Promotion, the Ontario Ministry of Health and Long Term Care, the Minist?re de la sant? et des services sociaux du Qu?bec, the Institut national de sant? publique du Qu?bec and the Fonds de la recherche en sant? du Qu?bec (FRSQ). Although agencies of the investigators provided infrastructure in support of the reported studies, the funders did not have a role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: DMS has previously received research grant funding from GlaxoSmithKline and Sanofi-Pasteur for separate studies. GDS and NB have received research grant funding from GlaxoSmithKline and Sanofi-Pasteur for separate studies. GB has received funding from GlaxoSmithKline for unrelated projects. SAVOIR contributor Allison McGeer has received investigator initiated research grant funding from GlaxoSmithKline, and speaking honoraria from GlaxoSmithKline and Sanofi-Pasteur.
Abbreviations: ADE, antibody-dependent enhancement; BC, British Columbia; CCHS, Canadian Community Health Survey; CI,, confidence interval; HCW, health care worker; ILI, influenza-like illness; NA, neuraminidase; NP, nasopharyngeal; OR, odds ratio; pH1N1, pandemic influenza A (H1N1); RR, risk ratio; SAR, secondary attack rate; SAVOIR, Studies of the Association of Vaccine on Influenza Risk; TIV, trivalent inactivated influenza vaccine; VE, vaccine effectiveness; WHO, World Health Organization
* E-mail: danuta.skowronski@bccdc.ca
? Members of the Canadian SAVOIR Team are listed in the Acknowledgments.
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