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Global Advisory Committee on Vaccine Safety, December 2011, Influenza A(H1N1)pdm09 vaccines (WHO, extracts, edited)

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  • Global Advisory Committee on Vaccine Safety, December 2011, Influenza A(H1N1)pdm09 vaccines (WHO, extracts, edited)

    [Source: World Health Oranization, Weekly Epidemiological Record, full PDF document: (LINK). Extract, edited.]

    Weekly epidemiological record / Relev? ?pid?miologique hebdomadaire

    10 february 2012, 87th year / 10 f?vrier 2012, 87e ann?e - No. 6, 2012, 87, 53?60 -

    Global Advisory Committee on Vaccine Safety, December 2011

    The Global Advisory Committee on Vaccine Safety (GACVS), an expert clinical and scientific advisory body, was established by WHO to provide independent, scientifically rigorous advice on vaccine safety issues of potential global importance.(1) GACVS held its 25th meeting in Geneva, Switzerland, on 7?8 December 2011.(2) The committee reviewed the following:
    1. New data related to (i) the safety profile of influenza A(H1N1)pdm09 vaccines and (ii) the risk of intussusception related to the use of second generation rotavirus vaccines.
    2. Generic issues concerning vaccine pharmacovigilance:
      • (i) safety of immunization during pregnancy and lactation
      • (ii) progress with the global vaccine safety network and
      • (iii) implementation of the Global Vaccine Safety Blueprint.

    Safety of influenza A(H1N1)pdm09 vaccines

    Overall, the safety information for the pandemic influenza vaccines continues to be reassuring. Other than the association of narcolepsy/cataplexy with an adjuvanted pandemic influenza vaccine in people aged 4?19 years, seen mainly in Finland and Sweden,(3) there were no new proven safety signals from passive surveillance systems.

    Population-based epidemiological studies on the association of narcolepsy with the adjuvanted pandemic vaccine (Pandemrix) have been completed in Sweden(4) and Finland. Adhering to the precautionary principle, the European Medical Agency?s Committee for Medicinal Products for Human Use concluded ?that the benefits of Pandemrix continue to outweigh its risks but that it may only be used in people <20 years of age if the recommended annual seasonal trivalent influenza is not available and if immunization against A(H1N1) is still needed, for instance in people at risk of the complications from infection?. Pandemrix marketing authorization has now expired and this vaccine is no longer in use. Epidemiological studies in other countries in Europe and Canada are under way.

    Immunological and animal model studies to help elucidate the biological mechanism of the observed association are also in progress.

    Although preliminary analyses of active surveillance studies for Guillain-Barr? syndrome in the United States, which evaluated both adjuvanted and non-adjuvanted pandemic influenza vaccines, indicated an increased risk, this finding has not been replicated elsewhere to date. Available data do not provide conclusive evidence for this increased risk. Were the risk to be confirmed, it would be much lower than that observed following the 1976 swine influenza vaccination campaign in the United States and would be similar to that observed with use of seasonal influenza vaccines.

    GACVS reviewed results from additional epidemiological studies on a possible association between influenza A(H1N1)pdm09 vaccines and certain autoimmune and other clinical syndromes. No major safety concerns appeared, although it was noted that the sample size or methodology of these studies might not have been optimal for establishing causal relations. The Committee acknowledged the need for further analysis in this area.

    The safety of pandemic vaccines when administered to pregnant women was reassuring. Data from an observational cohort study in Canada and from a birth and infant health registry in the United States did not point to any safety concerns related to pandemic vaccines among women during gestation or their offspring. Several studies on the safety of pandemic vaccines among pregnant women are still being completed in other regions.

    (1) See No. 41, 1999, pp. 337?338.

    (2) GACVS invited additional experts to present and discuss evidence related to particular topics. These experts included persons affiliated with: Medical Products Agency, Sweden; Erasmus University, Rotterdam, The Netherlands; Mount Sinai Hospital Toronto, Canada; Naval Health Research Center; San Diego, United States of America; Institut National de sant? publique du Qu?bec, Beauport, Canada; Children?s Hospital Boston, United States; Centers for Disease Control and Prevention, Atlanta, United States; Program for Applied Technologies in Health, Seattle, United States; London School of Hygiene and Tropical Medicine, London, United Kingdom.

    (3) Statement on narcolepsy and Pandemrix. Geneva, World health Organization, 2011 ( ; accessed January 2012).

    (4) Bardage C et al. Neurological and autoimmune disorders after vaccination against pandemic influenza A (H1N1) with a monovalent adjuvanted vaccine: population based cohort study in Stockholm, Sweden. BMJ, 2011, 343:d5956.