Re: Australia. Trivalent flu shots suspended after kids hospitalised, fatality
http://www.bmj.com/cgi/eletters/340/may04_2/c2419
Australia suspends seasonal flu vaccination of young children
BMJ.2010; 340: c2419
Adverse events following influenza vaccination in Australia--should we be surprised?
Peter Collignon, Peter Doshi, Tom Jefferson (7 May 2010)
There have been large numbers of major adverse reactions to this year's seasonal influenza vaccine in Australia, and the
vaccine has been suspended for use in children aged five and under [1,2]. These reactions have occurred across the country and
involved multiple batches of vaccine [2]. In the state of Western Australia where the problem was first detected,
reports suggest that of the 20,000 to 30,000 children vaccinated, more than 250 had adverse reactions and 55 had febrile convulsions before vaccination was suspended in young children [2]. Assuming all convulsions were in children, about one child in every 500 vaccinated had a febrile convulsion. Across Australia, media accounts indicate that more than 400 adverse reactions [3] including
77 cases of febrile convulsion [1] have been reported by regulators. While attention remains focused on reactions in very young children, reports suggest only one-third of the reactions may have occurred in children under five [4].
Although this situation has triggered considerable controversy in Australia, the story has attracted little to no media attention in the US and Europe. Similarly, the media has paid little attention to a US H1N1 federal vaccine safety advisory committee which recently reported detecting signals for Guillain-Barre syndrome (GBS), Bell's palsy, and thrombocytopenia in the monovalent H1N1 (swine flu) vaccine [5]. The same monovalent H1N1 antigen component under review in the US is scheduled to be added to the US trivalent seasonal vaccine and is contained in the Australian trivalent seasonal vaccine and will be given to children, pregnant women and adults [6].
Data from a previous Australian study of H1N1 vaccine show that a large percentage of children developed fevers following vaccination--in children less than 3 years, between three and six in every ten vaccinated, depending on dose [7,8]. The data also show a
dose response effect -- the larger the vaccine dose, the more severe the harms.
There was also an age relationship: children under the age of three developed fevers at more than twice the rate of older children [7,8].
The study was however underpowered to detect febrile convulsions at the current rates in Australia, with only 162 children below the age of three. The size problem was further aggravated by stratification by age group and antigen dose.
Presumably the vaccine manufacturer CSL, which sponsored the trial, and Australia?s regulatory body, the Therapeutic Goods Administration (TGA), which used this data in approving the vaccine for children, were aware of these important findings. But authors of the study published earlier this year
did not discuss the high incidence of fever associated with vaccination [7]; data were instead only reported in online-only supplementary tables [8].
Overall, the percentages of children under three who developed a fever after vaccination appear very high;
thirty five per cent with the 15 ug dose and 62% after a 30 ug dose [7,8].
Of those that received a 7.5 ug dose in the seasonal influenza vaccine, 23% develop a fever of >38 degrees Celsius [6].
The large number of children suffering harms--and subsequent suspension of the vaccine--challenges the assumption that regulators are ensuring the safety and efficacy of all marketed therapeutics.
Should we be surprised that these problems have occurred with influenza vaccine, a vaccine used for over 60 years, said to have "an established record of safety in all age groups"? [9] There are actually relatively little data on the effects of vaccinating young children against influenza [10].
Some manufacturers have even withheld data from public scrutiny amidst general indifference [10,11]. Evidence from all comparative influenza vaccine studies shows that harms, when they are investigated, are not reported consistently and systematically [10,11]. As pandemic vaccines are provided to governments and not individuals and manufacturers are indemnified for damages caused to users [12-14], there seem to be few incentives for investigation of harms.
Last winter, the likelihood that a child without risk factors would die from swine flu was less than one in a million [15]. When such a high proportion of children develop moderate to severe febrile reactions to the influenza vaccine, it's likely that more harm than good will occur by vaccinating the entire population.
If such a large proportion of children develop high fevers, it is also likely that a substantial number will develop febrile convulsions as a result of vaccination. It is thus surprising the vaccine was approved for this age group. It is also surprising that more explicit warnings about the high risk of adverse reactions were not given to parents when their children were being vaccinated. Passive surveillance (as in Australia and elsewhere) is a relatively weak mechanism to detect and evaluate post-vaccination adverse events [16].
Unlike most drugs, vaccines are used on a population basis triggered by public health policy. As such, evidence of their safety and efficacy needs to be extraordinarily rigorous and evaluation methods and data should be open to independent scrutiny. We need much better and larger studies on both safety and efficacy before we roll out influenza vaccine programs to all populations, especially to children who appear to have much higher rates of adverse reactions. Finally, decisions to use a vaccine in a population must consider its safety profile, but principally its effectiveness. There is poor evidence on how well influenza vaccines prevent any influenza complications in children [10] and other age groups. There is good evidence that influenza vaccines study reports cherry pick results and achieve spurious notoriety [17].
Exposing human beings to uncertain effects is a risky business.
References
1. Sweet M. Australia suspends seasonal flu vaccination of young children. BMJ. 2010 May 4;340(may04_2):c2419.
http://www.bmj.com/cgi/content/extract/340/may04_2/c2419
2. Reed J. Flu reactions cause still unclear [Internet]. 6minutes. 2010 Apr 27 [cited 2010 May 5];Available from:
http://www.6minutes.com.au/articles/z1/view.asp?id=516097
3. Bita N. Suspended flu jab caused fits in 67 kids [Internet]. The Australian. 2010 Apr 30 [cited 2010 May 5];Available from:
http://www.theaustralian.com.au/new...-fits-in-67-kids/story-e6frg8y6-1225860374357
4. Simmons A. Flu jab scare sparks call for surveillance system [Internet]. 2010 23T16:38:00+10:00 4 [cited 2010 Apr 24];Available from:
http://www.abc.net.au/news/stories/2010/04/23/2881522.htm
5. U.S. National Vaccine Advisory Committee. Report on 2009 H1N1 Vaccine Safety Risk Assessment [Internet]. 2010 Apr 28 [cited 2010 Apr 30];Available from:
http://www.hhs.gov/nvpo/nvac/reports/vsrawg_report_apr2010.html
6. CSL. Fluvax Inactivated Influenza Vaccine (Split Virion). Product information [Internet]. 2009 Nov [cited 2010 May 5];Available from:
http://www.csl.com.au/s1/cs/auhq/1217017237558/Web_Product_C/1196562642777/ProductDetail.htm
7. Nolan T, McVernon J, Skeljo M, Richmond P, Wadia U, Lambert S, et al. Immunogenicity of a Monovalent 2009 Influenza A(H1N1) Vaccine in Infants and Children: A Randomized Trial. JAMA. 2010 Jan 6;303(1):37-46.
http://jama.ama-assn.org/cgi/content/full/303/1/37
8. Nolan T, McVernon J, Skeljo M, Richmond P, Wadia U, Lambert S, et al. Immunogenicity of a Monovalent 2009 Influenza A(H1N1) Vaccine in Infants and Children: A Randomized Trial. JAMA. 2010 Jan 6;303(1):Supplementary online content.
http://jama.ama-assn.org/cgi/content/full/2009.1911/DC1
9. World Health Organization. Safety of pandemic vaccines [Internet]. 2009 Aug 6 [cited 2009 Aug 14];Available from:
http://www.who.int/csr/disease/swineflu/notes/h1n1_safety_vaccines_20090805/en/index.html
10. Jefferson T, Rivetti A, Harnden A, Di Pietrantonj C, Demicheli V. Vaccines for preventing influenza in healthy children. Cochrane Database Syst Rev. 2008;(2):CD004879.
http://www3.interscience.wiley.com/homepages/106568753/CD004879_standard.pdf
11. Jefferson T, Smith S, Demicheli V, Harnden A, Rivetti A. Safety of influenza vaccines in children. Lancet. 2005 Sep 3;366(9488):803-804.
12. Sebelius K. Pandemic Influenza Vaccines--Amendment [Internet]. 2009 Jun 25;Available from:
http://edocket.access.gpo.gov/2009/pdf/E9-14948.pdf
13. Lakhani N. Swine flu in Britain: The guessing game [Internet]. 2009 Jul 19 [cited 2009 Aug 11];Available from:
http://www.independent.co.uk/life-s...flu-in-britain-the-guessing-game-1752302.html