CHAPTER 12

• Jurisdiction: United States

CHAPTER 12 WHAT ADVERSE EFFECTS HAVE BEEN EXAMINED IN PAST VACCINE DEVELOPMENT PROJECTS?

It is important to understand what has been learned in studies of past vaccine effects. A study compared the measles-mumps-rubella vaccine (MMR+V) paired with the varicella vaccine, as opposed to the measles-mumps-rubella-varicella vaccine (MMRV) and observed children (twelve to twenty-three months old) for seven to ten days following vaccination.¹ The MMRV group experienced twice the risk of fever and subsequent febrile seizure than the MMR+V group. Pre-licensure studies revealed higher rates of fever as well as measles-like rash in the MMRV group, but in licensure stages, it was unknown that this increase was associated with increased risk of febrile seizure. As defined by the Mayo Clinic, a febrile seizure is a "convulsion in a child caused by a spike in body temperature . . . . [T]hey're usually harmless and typically don't indicate a serious health problem."²

An autoimmune response in the person being vaccinated may be triggered by adjuvants—molecules in the vaccine that enhance immunological responses within the body.³ Autoimmune disease results when the body's immune system starts attacking its own healthy tissue. When a vaccine elicits an immune response, there is a risk that this could result in an autoimmune disease. There has been no consistent...