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 influenzae meningitis. 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.
Or poor fucking diets, sedentary lifestyle and global warming (had to slide that in, someone else would have) ....
Reference...
https://www.chop.edu/centers-programs/vaccine-education-center/vaccines-and-other-conditions/vaccines-diabetes
Correlation does not equal causeation.