Results from the Studies and References (continued)[r6] The Swedish childhood diabetes study (1991)
When vaccinations were considered as possible risk factors for diabetes, a significant decrease in relative risk estimated as odds ratio (OR) was noted for measles vaccination (OR=0.69; 95% confidence limits 0.48–0.98). For vaccination against tuberculosis, smallpox, tetanus, whooping cough, rubella and mumps no significant effect on OR for diabetes was found. ... In conclusion, a protective effect of measles vaccination for Type 1 diabetes in childhood is indicated[r7] No major association of breast-feeding, vaccinations, and childhood viral diseases with early islet autoimmunity in the German BABYDIAB Study.(2000)
RESULTS: In offspring from mothers with type 1 diabetes, duration of exclusive and total breast-feeding did not differ between islet antibody-positive and -negative children, regardless of HLA genotype, and breast-feeding of 3 months or longer was not associated with protection from antibody development or diabetes onset. In offspring from diabetic fathers, non-statistically significant reductions in exclusive and total breast-feeding times were observed in the antibody-positive cohort. Neither type nor quantity of vaccinations (including Bacille Calmette-Guerin vaccine; haemophilus influenzae vaccine; diphtheria, tetanus, and pertussis vaccine; tick-born encephalitis vaccine; or measles, mumps, and rubella vaccine) were associated with the development of islet antibodies and diabetes. Measles, mumps, and rubella were not reported in children with islet antibodies or diabetes. CONCLUSIONS: This study showed no evidence that proposed environmental factors affect islet antibody development in the first 2 years of life in offspring from parents with type 1 diabetes.[r8] Lack of association between early childhood immunizations and beta-cell autoimmunity.
RESULTS: There was no difference between cases and control subjects in the proportion receiving hepatitis B (HBV), Haemophilus influenzae b (Hib), polio, or diphtheria tetanus pertussis (DTP) vaccines before 9 months of age; in the proportion receiving HBV at birth rather than later; or in the median age at first HBV, Hib, polio, or DTP vaccination. CONCLUSIONS: The results suggest that changing the early childhood immunization schedule would not affect the risk of developing beta-cell autoimmunity or type 1 diabetes.[r9] Lack of association between receipt of conjugate Haemophilus influenzae type b vaccine (HbOC) in infancy and risk of type 1 (juvenile onset) diabetes: long term follow-up of the HbOC efficacy trial cohort (2002)
We found no evidence that vaccination with Hib conjugate vaccine in infancy is associated with risk of [type-1] diabetes later in life.
[r10] Cumulative incidence of childhood-onset IDDM is unaffected by pertussis immunization. (1997)
RESULTS: No difference in cumulative incidence rate of IDDM up to the age of 12 years was found when the birth cohorts for 1978 and 1979 with high DTP vaccination coverage were compared with the cohorts of 1980 and 1981 with low pertussis vaccination coverage. CONCLUSIONS: The comparison of the cumulative incidence of IDDM, up to the age of 12 years, in birth cohorts with high and low exposure to pertussis vaccine does not support the hypothesis that pertussis could induce autoimmunity to the beta-cell that may lead to IDDM.[r11] Previous Exposure to Measles, Mumps, and Rubella but Not Vaccination During Adolescence Correlates to the Prevalence of Pancreatic and Thyroid Autoantibodies (1990)
Note that this title is a little tortured, but what they are trying to say is that vaccinations did not have an impact into the Prevalence of Pancreatic and Thyroid Autoantibodies, although people who were exposed to the actual disease (not the vaccination) did have a higher incidence of autoantibodies.
Results. The vaccination changed neither the prevalence nor the level of autoantibodies. Children with rubella antibodies before vaccination had higher levels of ICA than did the rubella seronegative children. In contrast, thyroid autoantibody levels and prevalence were lower in children with antibodies against measles, mumps, or both before vaccination than in children without those antibodies.
Conclusions. Previous natural infection or vaccination against measles, mumps, or both seemed to have an inhibitory effect on the development of thyroid autoantibodies. In contrast, children with previous exposure to rubella had higher levels of ICA. No evidence was found that MMR vaccination during adolescence may trigger autoimmunity.
[r12] Vaccination and autoimmune disease: what is the evidence? (2003) Review Paper
Over the past few decades, there has been a regular increase in the incidence of type 1 diabetes in most countries of the world. That childhood vaccines have been identified as a potential trigger event for this disease is, therefore, not surprising. This possibility has been assessed in a few epidemiological studies. Results of a case-control study done in Sweden in the mid-1980s did not indicate any great effect of vaccination against tuberculosis, smallpox, tetanus, pertussis, or rubella on risk of diabetes.
[This next paragraph refers to the Claussen paper discussed here as [r5]. Note that paper did not find different rates of type-1 diabetes between people vaccinated for HiB, and those not vaccinated.] However, one group has suggested that the timing of vaccination could be of importance, and that certain vaccines—eg, Haemophilus influenzae type b (Hib)—might increase the risk of type 1 diabetes if given at age 2 months or older. This theory was not confirmed by a 10-year follow-up study of more than 100000 Finnish children involved in a clinical trial of the Hib vaccine. In this study, there was no increased risk of diabetes when children who had received four doses of vaccine at age 3, 4, 6, and 14–18 months were compared with those who received only one dose at age 2 years. Furthermore, the risk of diabetes did not differ between children in the latter two cohorts and those in a non-concurrent unvaccinated group.
Additionally, findings of a study undertaken in four large health-maintenance organizations in the USA did not suggest an association between administration of routine childhood vaccines and increased risk of type 1 diabetes, irrespective of the timing of Hib or hepatitis B vaccination. Therefore, at this time, there are no serious indications of any great effect of childhood vaccines on the occurrence of type 1 diabetes.
[r13] Risk factors for type I diabetes mellitus in children in Austria (1999)
Conclusion ... No correlation could be found with dietary intake of cow's milk products in early infancy, vaccination and other environmental factors.[r14] No evidence that vaccines cause insulin dependent diabetes mellitus (1998) Meta Analysis
We conclude that at present there is no evidence of a link between IDDM and vaccination in humans.[r15] Consequence or coincidence?: The occurrence, pathogenesis and significance of autoimmune manifestations after viral vaccines (2004)
This review included a Medline search from 1966 to 2004, so it included a huge number of papers.
Whenever controlled studies of autoimmunity following viral vaccines were undertaken, no evidence of an association was found.
No evidence linking viral vaccines with type 1 diabetes, multiple sclerosis (MS) or inflammatory bowel disease can be found.
Why Do People Believe That Vaccines Cause Type-1 Diabetes? (Or Might Cause It?)
This is a subject much to broad to cover in a blog posting. However, I think there are some reasons to mention briefly:
First, since almost everyone gets vaccines, almost everyone who is diagnosed with type-1 diabetes has been vaccinated. And since almost everyone who is diagnosed with type-1 has been vaccinated, some of them will be recently vaccinated, just by chance.
Second, research which shows something is safe or does not cause a problem does not cause a big splash in newspapers, web sites, etc. That really came through as I searched for papers that showed vaccine safety. Many of them had no press/web/blog/facebook/twitter coverage at all!
Third, genetics, or lack of them. People understand that type-1 diabetes is a genetic disease, and they often notice that they don't know about any history of type-1 diabetes in their family. They think to themselves "I was told it was genetic, but it's obviously not in my case, so maybe it's vaccines. After all, I was vaccinated." This is bad logic on a number of levels. First, there are lots of environmental factors which have nothing to do with vaccines. Second, unless you know exactly how all your grandparent's (and great-grandparent's) descendants died, then you don't really know about type-1 in your family. If any of those descendants died young, it might well have been type-1 diabetes. Finally, remember that most people diagnosed with type-1 diabetes do not have a known history of type-1 in their families. But these same families often do have a history of other autoimmune diseases (with related genetics). In short, the lack of a family history of type-1 diabetes does not mean that vaccines are involved.
Fourth, and most importantly, there is clearly an infrastructure of people who think vaccines cause all kinds of problems. These people (and their web sites) are very vocal in pushing the idea that vaccines cause all kinds of problems (Autism, Type-1 Diabetes, ADD, bad test scores, allergies, Asthma, and on and on and on). They tend to seize on questionable (or outright fraudulent) research, while ignoring much better research which contradicts them. I want to stress that in these two blogs, I did not selectively report on the research. I included all the studies which I found.
I took a look at several of these web sites (Age Of Autism, NVIC, etc.) looking for studies which showed higher occurrence of type-1 diabetes in vaccinated people as compared to unvaccinated people. The only such studies I was able to find were two Claussen studies. One of those studies is discussed above. The other study was not a direct comparison study (that is, it did not compare people who got a vaccine to people who did not). Instead it mined other people's population studies for information. So while population studies are generally worse than direct comparison studies, this study was even worse than a population study.
Always Looking For More Studies
I'm always looking for more studies! So if you find any study not listed here, which compares type-1 diabetes rates in otherwise similar vaccinated and non-vaccinated populations (or to delayed-vaccination populations), please email me!
All the views expressed here are those of Joshua Levy, and nothing here is official JDRF or JDCA news, views, policies or opinions.