Journal Article

Effectiveness of an Adjuvanted Monovalent Vaccine Against the 2009 Pandemic Strain of Influenza A(H1N1)v in Stockholm County, Sweden

Åke Örtqvist, Ingela Berggren, Mona Insulander, Birgitta de Jong and Bo Svenungsson

in Clinical Infectious Diseases

Published on behalf of Infectious Diseases Society of America

Volume 52, issue 10, pages 1203-1211
Published in print May 2011 | ISSN: 1058-4838
Published online May 2011 | e-ISSN: 1537-6591 | DOI: http://dx.doi.org/10.1093/cid/cir182
Effectiveness of an Adjuvanted Monovalent Vaccine Against the 2009 Pandemic Strain of Influenza A(H1N1)v in Stockholm County, Sweden

More Like This

Show all results sharing these subjects:

  • Infectious Diseases
  • Immunology
  • Public Health and Epidemiology
  • Microbiology

GO

Show Summary Details

Preview

Background. Vaccination against the pandemic influenza A(H1N1)v was performed in many countries during 2009, but population-based data on vaccine effectiveness are lacking.

Methods. We conducted a prospective cohort study involving all inhabitants in Stockholm County (n = 2,019,183) who were offered a monovalent AS03-adjuvanted influenza A(H1N1)v vaccine (Pandemrix, GSK), between 12 October and 31 December 2009. Overall vaccine coverage was 52%. A Web-based register with data on all vaccinated was linked by unique personal identification number to mandatory reports of influenza A(H1N1)v diagnoses. Vaccine failure was defined as a diagnosis or admission to hospital because of influenza >14 days after vaccination. Risk factors associated with vaccine failure were investigated by conditional stepwise logistic regression in a nested case–control study. The weekly incidence rate ratio for being diagnosed with influenza among vaccinated versus nonvaccinated persons was calculated.

Results. Vaccine failure was seen in 25 patients, 11 children and 14 adults, of 2594 patients diagnosed with influenza A(H1N1)v. Compared with age-matched controls, patients with vaccine failure were more often immunocompromised (Hazard Ratio, 4.89; 95% confidence interval [CI], 2.19–10.89). During the 4 weeks with maximum influenza activity, the relative risk per week for an influenza A(H1N1)v diagnosis in the vaccinated population was .06 (95% CI .008–.41), .13 (95% CI .06–.27), .05 (95% CI .02–.12), and .07 (95% CI .03–.15), respectively, corresponding to a weekly vaccine effectiveness of 87–95%.

Conclusions. The monovalent AS03-adjuvanted influenza vaccine was highly effective in prevention of the pandemic influenza in Stockholm County. A single dose seemed to be sufficient in most, both children and adults, except in immunocompromised hosts.

Journal Article.  4397 words.  Illustrated.

Subjects: Infectious Diseases ; Immunology ; Public Health and Epidemiology ; Microbiology

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.