Effectiveness of H1N1 vaccine for the prevention of pandemic influenza in Scotland, UK

a retrospective observational cohort study

Colin Simpson, Lewis Duthie Ritchie, Chris Robertson, Aziz Sheikh, Jim McMenamin

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Background
A targeted vaccination programme for pandemic H1N1 2009 influenza was introduced in Scotland, UK, in October, 2009. We sought to assess the effectiveness of this vaccine in a sample of the Scottish population during the 2009–10 pandemic.

Methods
We assessed the effectiveness of the Scottish pandemic H1N1 2009 influenza vaccination with a retrospective cohort design. We linked data of patient-level primary care, hospital records, death certification, and virological swabs to construct our cohort. We estimated vaccine effectiveness in a nationally representative sample of the Scottish population by establishing the risk of hospital admission and death (adjusted for potential confounders) resulting from influenza-related morbidity in vaccinated and unvaccinated patients and laboratory-confirmed cases of influenza H1N1 2009 in a subset of patients.

Findings
Pandemic H1N1 2009 influenza vaccination began in week 43 of 2009 (Oct 21, 2009) and was given to 38¿296 (15·5%, 95% CI 15·4–15·6) of 247¿178 people by the end of the study period (Jan 31, 2010). 208¿882 (85%) people were unvaccinated. There were 5207 emergency hospital admissions and 579 deaths in the unvaccinated population and 924 hospital admissions and 71 deaths in the vaccinated population during 23¿893¿359 person-days of observation. The effectiveness of H1N1 vaccination for prevention of emergency hospital admissions from influenza-related disorders was 19·5% (95% CI 0·8–34·7). The vaccine's effectiveness in preventing laboratory-confirmed influenza was 77·0% (95% CI 2·0–95·0).

Interpretation
Pandemic H1N1 2009 influenza vaccination was associated with protection against pandemic influenza and a reduction in hospital admissions from influenza-related disorders in Scotland during the 2009–10 pandemic.

Funding
National Institute for Health Research Health Technology Assessment Programme (UK).

Original languageEnglish
Pages (from-to)696-702
Number of pages7
JournalLancet Infectious Diseases
Volume12
Issue number9
Early online date25 Jun 2012
DOIs
Publication statusPublished - Sep 2012

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Scotland
Pandemics
Human Influenza
Observational Studies
Cohort Studies
Vaccines
Vaccination
Population
Emergencies
Biomedical Technology Assessment
Hospital Records
Certification
Primary Health Care
Observation
Morbidity
Health

Keywords

  • H1N1
  • pandemic influenza
  • vaccine effectiveness
  • data linkage

Cite this

Effectiveness of H1N1 vaccine for the prevention of pandemic influenza in Scotland, UK : a retrospective observational cohort study. / Simpson, Colin; Ritchie, Lewis Duthie; Robertson, Chris; Sheikh, Aziz; McMenamin, Jim.

In: Lancet Infectious Diseases, Vol. 12, No. 9, 09.2012, p. 696-702.

Research output: Contribution to journalArticle

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title = "Effectiveness of H1N1 vaccine for the prevention of pandemic influenza in Scotland, UK: a retrospective observational cohort study",
abstract = "Background A targeted vaccination programme for pandemic H1N1 2009 influenza was introduced in Scotland, UK, in October, 2009. We sought to assess the effectiveness of this vaccine in a sample of the Scottish population during the 2009–10 pandemic. Methods We assessed the effectiveness of the Scottish pandemic H1N1 2009 influenza vaccination with a retrospective cohort design. We linked data of patient-level primary care, hospital records, death certification, and virological swabs to construct our cohort. We estimated vaccine effectiveness in a nationally representative sample of the Scottish population by establishing the risk of hospital admission and death (adjusted for potential confounders) resulting from influenza-related morbidity in vaccinated and unvaccinated patients and laboratory-confirmed cases of influenza H1N1 2009 in a subset of patients. Findings Pandemic H1N1 2009 influenza vaccination began in week 43 of 2009 (Oct 21, 2009) and was given to 38¿296 (15·5{\%}, 95{\%} CI 15·4–15·6) of 247¿178 people by the end of the study period (Jan 31, 2010). 208¿882 (85{\%}) people were unvaccinated. There were 5207 emergency hospital admissions and 579 deaths in the unvaccinated population and 924 hospital admissions and 71 deaths in the vaccinated population during 23¿893¿359 person-days of observation. The effectiveness of H1N1 vaccination for prevention of emergency hospital admissions from influenza-related disorders was 19·5{\%} (95{\%} CI 0·8–34·7). The vaccine's effectiveness in preventing laboratory-confirmed influenza was 77·0{\%} (95{\%} CI 2·0–95·0). Interpretation Pandemic H1N1 2009 influenza vaccination was associated with protection against pandemic influenza and a reduction in hospital admissions from influenza-related disorders in Scotland during the 2009–10 pandemic. Funding National Institute for Health Research Health Technology Assessment Programme (UK).",
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T1 - Effectiveness of H1N1 vaccine for the prevention of pandemic influenza in Scotland, UK

T2 - a retrospective observational cohort study

AU - Simpson, Colin

AU - Ritchie, Lewis Duthie

AU - Robertson, Chris

AU - Sheikh, Aziz

AU - McMenamin, Jim

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N2 - Background A targeted vaccination programme for pandemic H1N1 2009 influenza was introduced in Scotland, UK, in October, 2009. We sought to assess the effectiveness of this vaccine in a sample of the Scottish population during the 2009–10 pandemic. Methods We assessed the effectiveness of the Scottish pandemic H1N1 2009 influenza vaccination with a retrospective cohort design. We linked data of patient-level primary care, hospital records, death certification, and virological swabs to construct our cohort. We estimated vaccine effectiveness in a nationally representative sample of the Scottish population by establishing the risk of hospital admission and death (adjusted for potential confounders) resulting from influenza-related morbidity in vaccinated and unvaccinated patients and laboratory-confirmed cases of influenza H1N1 2009 in a subset of patients. Findings Pandemic H1N1 2009 influenza vaccination began in week 43 of 2009 (Oct 21, 2009) and was given to 38¿296 (15·5%, 95% CI 15·4–15·6) of 247¿178 people by the end of the study period (Jan 31, 2010). 208¿882 (85%) people were unvaccinated. There were 5207 emergency hospital admissions and 579 deaths in the unvaccinated population and 924 hospital admissions and 71 deaths in the vaccinated population during 23¿893¿359 person-days of observation. The effectiveness of H1N1 vaccination for prevention of emergency hospital admissions from influenza-related disorders was 19·5% (95% CI 0·8–34·7). The vaccine's effectiveness in preventing laboratory-confirmed influenza was 77·0% (95% CI 2·0–95·0). Interpretation Pandemic H1N1 2009 influenza vaccination was associated with protection against pandemic influenza and a reduction in hospital admissions from influenza-related disorders in Scotland during the 2009–10 pandemic. Funding National Institute for Health Research Health Technology Assessment Programme (UK).

AB - Background A targeted vaccination programme for pandemic H1N1 2009 influenza was introduced in Scotland, UK, in October, 2009. We sought to assess the effectiveness of this vaccine in a sample of the Scottish population during the 2009–10 pandemic. Methods We assessed the effectiveness of the Scottish pandemic H1N1 2009 influenza vaccination with a retrospective cohort design. We linked data of patient-level primary care, hospital records, death certification, and virological swabs to construct our cohort. We estimated vaccine effectiveness in a nationally representative sample of the Scottish population by establishing the risk of hospital admission and death (adjusted for potential confounders) resulting from influenza-related morbidity in vaccinated and unvaccinated patients and laboratory-confirmed cases of influenza H1N1 2009 in a subset of patients. Findings Pandemic H1N1 2009 influenza vaccination began in week 43 of 2009 (Oct 21, 2009) and was given to 38¿296 (15·5%, 95% CI 15·4–15·6) of 247¿178 people by the end of the study period (Jan 31, 2010). 208¿882 (85%) people were unvaccinated. There were 5207 emergency hospital admissions and 579 deaths in the unvaccinated population and 924 hospital admissions and 71 deaths in the vaccinated population during 23¿893¿359 person-days of observation. The effectiveness of H1N1 vaccination for prevention of emergency hospital admissions from influenza-related disorders was 19·5% (95% CI 0·8–34·7). The vaccine's effectiveness in preventing laboratory-confirmed influenza was 77·0% (95% CI 2·0–95·0). Interpretation Pandemic H1N1 2009 influenza vaccination was associated with protection against pandemic influenza and a reduction in hospital admissions from influenza-related disorders in Scotland during the 2009–10 pandemic. Funding National Institute for Health Research Health Technology Assessment Programme (UK).

KW - H1N1

KW - pandemic influenza

KW - vaccine effectiveness

KW - data linkage

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JF - Lancet Infectious Diseases

SN - 1473-3099

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ER -