Intended for healthcare professionals


Public should be told that vaccines may have long term adverse effects

BMJ 1999; 318 doi: (Published 16 January 1999) Cite this as: BMJ 1999;318:193
  1. John Barthelow Classen (Classen{at}, President.*,
  2. David C Classen, Infectious disease physician.*
  1. Classen Immunotherapies, 6517 Montrose Avenue, Baltimore, MD 21212, USA
  2. Division of Infectious Diseases, LDS Hospital, Salt Lake City, UT, USA

    EDITOR—Jefferson's editorial about vaccination and its adverse effects mentions our research.1 We found that immunisation starting at birth was associated with a decreased risk of insulin dependent diabetes, while immunisation starting after age 2months was associated with an increased risk of diabetes in both rodents and humans.2 We initiated a collaboration with Dr Jaakko Tuomilehto to study the effect of Haemophilus influenzae type b vaccine on the incidence of diabetes. Roughly116000 Finnish children were randomised to receive either four doses of the vaccine, starting at 3months of age, or one dose at 24months of age.3 We calculated the incidence of insulin dependent diabetes in both groups until age 10and in a group that did not receive the vaccine—a cohort that included all 128500 children born in Finland in the 24months before the study of the vaccine began.

    A conference was held in Bethesda, Maryland, in May 1998to discuss our data. At the conference we stated that the data on the vaccine support our published findings that immunisation starting after the age of 2months is associated with an increased risk of diabetes. Our analysis is further supported by a similar rise in diabetes after immunisation with H influenzaetype b vaccine in the United States4 and United Kingdom.5 Furthermore, the increased risk of diabetes in the vaccinated group exceeds the expected decreased risk of complications of H influenzae meningitis.

    Research into immunisation has been based on the theory that the benefits of immunisation far outweigh the risks from delayed adverse events and so long term safety studies do not need to be performed. When looking at diabetes—only one potential chronic adverse event—we found that the rise in the prevalence of diabetes may more than offset the expected decline in long term complications of H influenzaemeningitis. Thus diabetes induced by vaccine should not be considered a rare potential adverse event. The incidence of many other chronic immunological diseases, including asthma, allergies, and immune mediated cancers, has risen rapidly and may also be linked to immunisation.

    We believe that the public should be fully informed that vaccines, though effective in preventing infections, may have long term adverse effects. An educated public will probably increasingly demand proper safety studies before widespread immunisation. We believe that the outcome of this decision will be the development of safer vaccine technology.

    * The methods used in this research are covered by patents owned by Classen Immunotherapies. John Classen holds shares in Classen Immunotherapies; David Classen owns no shares in the company, receives no funding from it, and has no financial ties to it or to this research.