2009 Swine flu vaccine

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See also the main Swine influenza page.

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Applies in England

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Some is also applicable elsewhere in the UK

Vaccines were produced against swine flu and rapidly brought to market. They are produced using similar methods, and are similar products, to those used in seasonal influenza. The UK had contracts with Baxter (Celvapan®) and GSK (Pandemrix®); in other countries from other manufacturers such as Novartis are being used.

Information about the vaccination programme was posted by the Department of Health at the swine flu page on its website, and on its immunisation website.


Who were offered the vaccine

According to the Department of Health:[1][2]

QuotationMarkLeft.png Following advice from independent expert committees including the Joint Committee for Vaccination and Immunisation (JCVI), the following groups should be prioritised for vaccination in the following order, once the vaccine has been licensed:

  1. individuals aged six months and up to 65 years in the current seasonal flu vaccine clinical at-risk groups
  2. all pregnant women, subject to licensing conditions on trimesters
  3. household contacts of immunocompromised individuals
  4. people aged 65 and over in the current seasonal flu vaccine clinical at-risk groups

These groups were selected because they are at highest risk of severe illness. In practice, it is likely that as vaccines become available, priority groups i-iii may be vaccinated concurrently, rather than in order of priority.

Frontline health and social care workers In addition to these groups, frontline health and social care workers were offered the vaccine at the same time as the first clinical risk group as they are at increased risk of infection and of transmitting that infection to susceptible patients. Frontline healthcare workers eligible for this vaccination programme are those also eligible for seasonal influenza vaccination, as detailed in Immunisation against infectious disease (The Green Book). Eligibility guidance for vaccination for frontline health and social care workers is included in the annexes to this letter.

Subsequent use of the vaccine in the wider healthy population will depend upon information about the evolving nature of the pandemic as well as new and emerging clinical data on the use of the vaccine. These will be kept under close review. QuotationMarkRight.png

Others have argued that other sequences might be preferable; for example, vaccinating children first because closing of schools is socially disruptive because carers are obliged to take time off work, and it interrupts children's education;[3] and because children are particularly effective at spreading their respiratory and gastrointestinal infections to others.

Implementation Update

"Phase two" of the programme extended vaccination more widely, including to children age >6 months to <=5 years. The Government had failed to offer a sufficient payment to cover GPs costs, so a negotiated agreement was not been reached nationally (see Pulse story and DH press release).

A single dose of vaccine was now considered sufficient for children - see Ian Dalton "Dear Colleague" letter.


Two doses were recommended, given at least three weeks apart. The same vaccine must be used for both doses – they are not interchangeable – so accurate recording of the first dose is essential to ensure that individuals get two doses of the same vaccine.[4][5]

Increasing number of publications, however, seem to suggest that - for many of the vaccines, and at least for people aged 10 years or more - a single dose of is sufficient.

Further Update

A single dose is now considered sufficient, except for people who are immunosuppressed. (Depending on the type of immunosuppression a single dose may or may not suffice, but the guidance is vague about this.)

Vaccine safety

As ever, antivaccinists managed to get their messages more quickly and effectively than healthcare providers and ministries. Many of their messages were based on the concerns that a vaccine campaign against a previous swine flu virus in 1976 may have caused Guillain-Barre syndrome. It is by no means certain that this was the case:[6] and if it was the case, the number of cases was small. There is a small increase in narcolepsy associated with Pandemrix use in those under 20[7]. The risk of most adverse consequences, including death and Guillain-Barre syndrome, is much higher with influenza disease than with the vaccine:

QuotationMarkLeft.png In 1976, the national swine influenza vaccination program in the United States was suspended because of an increased risk of Guillain-Barre syndrome. Subsequent studies of seasonal influenza vaccine have given conflicting results. The authors used the self-controlled case series method to investigate the relation of Guillain-Barre syndrome with influenza vaccine and influenza like illness using cases recorded in the General Practice Research Database from 1990 to 2005 in the United Kingdom. The relative incidence of Guillain-Barre syndrome within 90 days of vaccination was 0.76 (95% confidence interval: 0.41, 1.40). In contrast, the relative incidence of Guillain-Barre syndrome within 90 days of an influenza like illness was 7.35 (95% confidence interval: 4.36, 12.38), with the greatest relative incidence (16.64, 95% confidence interval: 9.37, 29.54) within 30 days. The relative incidence was similar (0.89, 95% confidence interval: 0.42, 1.89) when the analysis was restricted to a subset of validated cases. The authors found no evidence of an increased risk of Guillain-Barre syndrome after seasonal influenza vaccine. The finding of a greatly increased risk after influenza-like illness is consistent with anecdotal reports of a preceding respiratory illness in Guillain-Barre syndrome and has important implications for the risk/benefit assessment that would be carried out should pandemic vaccines be deployed in the future. QuotationMarkRight.png

. With regard specifically to narcolepsy there is an association with H1N1 infection and it was unclear if the risk in the predisposed is similar with infection or vaccination[8]. It took at least 8 years for the process of legal discovery associated with narcolepsy risk, which remains controversial and unproven, to reveal that the relative risk of adverse effects were higher for Pandemrix® than the other Swine flu vaccines. Some of this discrepancy could be because some of the other vaccines were used predominantly in countries with poor adverse event reporting culture. A legal complexity revolves around when relevant authorities were aware of the perhaps 5 to 10 fold increase in relative risk (at earliest by December 2009, which was after most use in UK, indeed Arepanrix® one of the apparently safer vaccines, only obtained EMEA authorisation in March 2010) and not if the amount of flu related complications prevented by immunisation out weighed the risk. At a serious adverse risk rate of 76 per million doses Pandemrix® which contained the adjuvant AS03 was worse than other 2009 Swine flu vaccines with a rate of 8/million. To help put this relative risk in perspective it is very similar to the increased relative risk pregnancy has of serious outcome compared to influenza infection in non pregnant women. The absolute population risk of the 2009 Swine flu virus is known from Hong Kong where serious outcome (death or hospitalisation) affected 0.15 % of the population[9]. There are over two orders of magnitude difference between 76/million and 1500/million, and as subsequent studies showed Pandemrix was 92% effective in some populations in reducing hospitalisation for 2 flu seasons[10]. Accordingly use of the vaccine is likely to have saved a lot more hospitalisations and deaths than the serious adverse effects of the vaccine.

External links


  1. http://www.dh.gov.uk/en/Publicationsandstatistics/Lettersandcirculars/Dearcolleagueletters/DH_104267 Donaldson L. New H1N1v influenza: current situation and next steps. London: Department of Health, 2009 (13 August) (Gateway reference number 12421); 1-2]
  2. Department of Health. Vaccine Update 160. London: Department of Health, 2009 (June/July)
  3. The Lancet Infectious D. Pandemic influenza: the new wave. The Lancet Infectious Diseases 2009;9(10):583-583.
  4. Salisbury D. H1N1 Swine flu vaccination programme. London: Department of Health, 2009 (26 June)
  5. Department of Health. Vaccine Update 160. London: Department of Health, 2009 (June/July)
  6. Evans D, Cauchemez S, Hayden FG. "Prepandemic" immunization for novel influenza viruses, "swine flu" vaccine, guillain-barre syndrome, and the detection of rare severe adverse events. J Infect Dis 2009;200(3):321-8
  7. European Medicines Agency recommends restricting use of Pandemrix 21 July 2011
  8. Dauvilliers Y, Montplaisir J, Cochen V, Desautels A, Einen M, Lin L, Kawashima M, Bayard S, Monaca C, Tiberge M, Filipini D, Tripathy A, Nguyen BH, Kotagal S, Mignot E. Post-H1N1 narcolepsy-cataplexy. Sleep. 2010 Nov; 33(11):1428-30.
  9. L Yang, CM Wong, SSS Chiu, BJ Cowling, JSM Peiris Estimation of excess mortality and hospitalisation associated with the 2009 pandemic influenza Hong Kong Med J 2018;24(Suppl 6):S19-22
  10. Örtqvist Å, Bennet R, Hamrin J, Rinder MR, Lindblad H, Öhd JN, Eriksson M. Long term effectiveness of adjuvanted influenza A(H1N1)pdm09 vaccine in children. Vaccine. 2015 May 21;33(22):2558-61. doi: 10.1016/j.vaccine.2015.04.011
  11. Joint GPC / RCGP / DH pandemic influenza guidance for GP practices, specific to swine flu (H1N1) (Updated 08 December 2009)