Some health concerns have been raised, and research worldwide has sought to clarify the issue.
Arthritis
Some vaccines cause transient joint pains, but true arthritis and other auto-immune illnesses such as lupus are not increased by vaccination.
Multiple sclerosis Someone who already has MS can have a relapse if their immune system is given extra work to do, such as by vaccination, but the risk of developing MS is not changed.
Cancer There is no increased risk of cancer following vaccination. In fact, cancer rates after vaccination are sometimes lower, eg. liver cancer rates fall with hepatitis B vaccination.
For further information and references see Why vaccinate? article
