Disproving Another Vaccination Scare

The Danish Civil Registration System, implemented since 1968, enabled Hviid and colleagues to perform a very powerful longitudinal study examining the proposed association between vaccination and incidence of type 1 diabetes mellitus (T1DM). Because each Dane is assigned a unique identification number, the population can be followed longitudinally and individual data on different variables can be independently compiled from multiple registry sources, thereby eliminating selection and recall biases. Using this rationale, Hviid et al. followed through December, 2001 all children born in Denmark January 1, 1990 to December 31, 2000 (n = 739,694), and identified 681 cases of diabetes. Using Poisson regression models, the rate ratios for diabetes among children who had received at least one dose of the different vaccines versus unvaccinated children ranged from 0.91 to 1.14 (95% confidence intervals ranged 0.71-1.57). [hemophilus influenza B 1.02; DPT 0.94; DPTP 1.06; MMR 1.08; and oral polio 0.74 (p>0.05)] The rate ratio for maximal number of vaccinations (13) versus no vaccinations was 1.32 [0.42-4.10]. Likewise, the rate ratios did not increase in the 2–4 years after vaccination, the proposed time of disease clustering. Of the 681 cases of diabetes, 26 had siblings with diabetes. Even in this genetically predisposed subgroup (rate ratio for diabetes in siblings versus no siblings was 40.1 [26.9-59.6]), the rate ratios for diabetes did not significantly increase with vaccination status.

Hviid A, Stellfeld M, Wohlfahrt J, Melbye M. Childhood vaccination and type 1 diabetes. New Engl J Med 2004;350:1398-1404.

Editor’s Comment: The increasing incidence of T1DM has been associated temporally with the widespread introduction of general childhood immunizations. Further, T1DM has been described as clustering 3–4 years after vaccination. This has led some to conclude that vaccination plays a role in the development of T1DM. Associations are NEVER sufficient to prove causation. Thankfully, these authors performed such a terrific study which clarified that childhood vaccinations did not increase the risk of developing T1DM. For recent reviews of the pathogenesis of T1DM, see references 1–3, and reference 4 for immunologic effects of vaccination.

Adda Grimberg, MD

References - (linked to )

1. Virtanen SM, Knip M. Nutritional risk predictors of beta cell autoimmunity and type 1 diabetes at a young age. Am J Clin Nutr. 2003;78:1053-1067.
2. Rabinovitch A. Immunoregulation by cytokines in autoimmune diabetes. Adv Exp Med Biol 2003;520:159-193.
3. Casares S, Brumeanu TD. Insights into the pathogenesis of type 1 diabetes: a hint for novel immunospecific therapies.Curr Mol Med 2001;1:357-378.
4. Offit PA, Hackett CJ. Addressing parents' concerns: do vaccines cause allergic or autoimmune diseases? Pediatrics 2003;111:653-9.