Vaccine Injury - Adverse Events Following Immunization

Adverse Events Following Immunization

All vaccines may cause side effects, and immunization safety is a real concern. Unlike most other medical interventions, vaccines are given to healthy people, and people are far less willing to tolerate vaccines' adverse effects than adverse effects of other treatments. As the success of immunization programs increases and the incidence of disease decreases, public attention shifts away from the risks of disease to the risk of vaccination.

Concerns about immunization safety often follow a pattern. First, some investigators suggest that a medical condition of increasing prevalence or unknown cause is an adverse effect of vaccination. The initial study, and subsequent studies by the same group, have inadequate methodology, typically a poorly controlled or uncontrolled case series. A premature announcement is made of the alleged adverse effect, resonating with individuals suffering the condition, and underestimating the potential harm to those whom the vaccine could protect. The initial study is not reproduced by other groups. Finally, it takes several years to regain public confidence in the vaccine.

Controversies in this area revolve around the question of whether the risks of adverse events following immunization outweigh the benefits of saving people from tragic outcomes of common diseases. There is some scientific evidence that immunizations can cause serious adverse effects, such as gelatin measles-mumps-rubella vaccine (MMR) causing anaphylaxis, a severe allergic reaction. Controversy exists over whether conditions such as autism are caused by vaccines. Allegations particularly focus on the MMR vaccine and on thiomersal, a preservative that is used in vaccines routinely given to U.S. children less than 24 months of age. Current scientific evidence does not support causation for these disorders. Nearly 5,000 U.S. families of children diagnosed with autism have claims for compensation from a federal fund, saying that their health problems were caused by common childhood vaccines. In one autism-related case, the government conceded that the child had a pre-existing mitochondrial disorder with autism-like symptoms aggravated by simultaneous immunizations against nine diseases.