Influenza

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effects of the vaccine

Although one can read differing opinions of the flu vaccine's efficacy, it has been admitted, by the CDC and other experts, that the vaccine did not work well in the 2003-2004 season because the strain of flu virus differed from the strain from which the vaccine had been prepared.[1-2] Historically, the flu vaccine has been made from cultures of viruses taken in Asia from migrating ducks. (Over the years, an association has been established between bird and pig viruses and the following year's epidemics of human flu.) The vaccine is then preparedred from the body fluids of chick embryos inoculated with a specific type or types of influenza virus. The strains of flu virus in the vaccine are inactivated with formaldehyde and preserved with thimerosal, the mercury derivative. The vaccine protects against only the three specific viral strains of flu included in any given year's vaccine.

Because the influenza vaccine is grown on hen eggs, the AAP recommends that children with actual or suspected allergic reactions to chicken or egg protein not be given the flu vaccine unless they undergo desensitization. Given the unpredictability of matching each year's flu vaccine to the actual strain of flu virus that will later spread among the human population, it is highly questionable whether the vaccine is anything more than marginally effective. The CDC report on the 1994-1995 flu season stated that 87 percent of influenza A virus samples and 76 percent of influenza B virus samples were not similar to that year's vaccine.[3] Although researchers today are more accurate in matching vaccine to virus, it is still a hit-or-miss affair that makes the vaccine's efficacy inherently unpredictable. According to "Recommendations for Influenza Immunization of Children," an AAP policy statement, "Protective efficacy against influenza illness confirmed by positive culture varies between 30 percent and 95 percent." [4-8]

risks of the vaccine

The very people who traditionally have been encouraged to get the flu vaccine’Äìthe elderly and the immunocompromised (those with weak or impaired immune systems)’Äìare those most likely to suffer from acute consequences of the vaccine's side effects. The CDC lists these effects as fever, fatigue, muscle aches, and headache. These symptoms, which sound remarkably similar to flu symptoms, are exactly what many people experience after taking the vaccine. More serious side effects have also been noted that specifically link the flu vaccine to Guillain-Barré syndrome (GBS), an autoimmune nervous-system reaction characterized by unstable gait and loss of sensation and muscle control.[9]

In 1976, the US government mounted a mass vaccination program in which 45 million Americans received the swine flu vaccine. Statistical studies have confirmed a causal relationship between the vaccine and GBS. During that year, the rate of GBS in Ohio was 13.3 per 1,000,000 in vaccine recipients, compared to 2.6 per 1,000,000 in nonrecipients.[10] These statistics left doctors reluctant to administer the flu vaccine, and diminished the trust that the public had in the flu vaccine campaign. More recently, an increased risk for GBS occurred in patients during the six weeks following the administration of flu vaccine in the 1992-1993 and 1993-1994 flu seasons.[11]

Since 2001, the CDC has recommended that all pregnant women receive the flu vaccine in their second or third trimester.[12] This recommendation has been made despite the fact that the vaccine remains a Category C drug (one for which the risk to pregnant women and their fetuses is unknown). The vaccine's mercury content is a major factor in its potential impact on fetal brain development, but no adequate studies have been conducted to monitor the flu vaccine's safety for mother or fetus. According to the CDC, two groups are most vulnerable to thimerosal, or ethyl mercury: the fetus, and children ages 14 or younger.[13] A 1999 article in the American Journal of Epidemiology stated in regard to ingested mercury, "The greatest susceptibility to methyl mercury neurotoxicity occurs during late gestation."[14] Even the CDC Advisory Committee on Immunization Practices, despite its own recommendation, states, "additional data are needed to confirm the safety of vaccination during pregnancy."[15]

next...The FluMist Vaccine

Footnotes

  1. "Flu Shot Unable to Combat Virus Strain," http://abcnews.go.com/wire/Living/ap20031215_870.html
  2. "Panel of Vaccine Experts Fear Flu Shot May Not Work Well in Combating This Year's Virus Strain," www.nvic.org/PressReleases/prfluvaccine.htm.
  3. Randall Neustaedter, The Vaccine Guide (Berkeley, CA: North Atlantic Books, 2003): 159.
  4. W. C. Gruber, L. H. Taber, W. P. Glezen et al., "Live Attenuated and Inactivated Influenza Vaccine in School-Age Children," Am J Dis Child 144 (1990): 595’Äì600.
  5. T. Heikkinen, O. Ruuskanen, M. Waris et al., "Influenza Vaccination in the Prevention of Acute Otitis Media in Children," Am J Dis Child 145 (1991): 445’Äì448.
  6. E. S. Hurwitz, M. Haber, A. Chang et al., "Studies of the 1996’Äì1997 Inactivated Influenza Vaccine among Children Attending Day Care: Immunologic Response, Protection against Infection, and Clinical Effectiveness," J Infect Dis 182 (2000): 1218’Äì1221.
  7. K. M. Neuzil, W. D. Dupont, P. F. Wright et al., "Efficacy of Inactivated and Cold-Adapted Vaccines against Influenza A Infection, 1985 to 1990: The Pediatric Experience," Pediatric Infect Dis J 20 (2001): 733’Äì740.
  8. A. Hoberman, D. P. Greenberg, J. L. Paradise et al., "Effectiveness of Inactivated Influenza Vaccine in Preventing Acute Otitis Media in Young Children: A Randomized Controlled Trial," JAMA 290 (2003): 1608’Äì1616.
  9. T. Lasky et al., "Guillain-Barrˆ© Syndrome and the 1992’Äì1993 and 1993’Äì1994 Influenza Vaccines," New England Journal of Medicine 339 (1998): 1797’Äì1802.
  10. J. S. Marks and T. J. Halpin, "Guillain-Barrˆ© Syndrome in Recipients of a New Jersey Influenza Vaccine," JAMA 243, no. 42 (1980): 2490’Äì2494.
  11. See Note 13.
  12. Centers for Disease Control, www.cdc.gov/nip/publications/VIS/vis-flu.txt.
  13. Centers for Disease Control, www.cdc.gov/nip/vacsafe/concerns/thimerosal/faqs-thi merosal.htm.
  14. P. Grandjean et al., "Methylmercury Exposure Biomarkers as Indicators of Neurotoxicity in Children Aged 7 Years," American Journal of Epidemiology 150, no. 3 (1999): 301’Äì305.
  15. Centers for Disease Control, "Prevention and Control of Influenza: Recommendatons of the Advisory Committee on Immunization Practices (ACIP)" MMWR (b) (RR04) (2001): 1’Äì46.