Vaccination is one of the greatest achievements of medicine and has spared millions of people the effects of devastating diseases. Before vaccines became widely used, infectious diseases killed thousands of children and adults each year in the United States.

Before 1985, Haemophilus Influenzae type b (Hib) caused serious infections in 20,000 children each year, including meningitis (12,000 cases) and pneumonia (7,500 cases). In 1998 (after Hib Vaccination), there were 54 cases of Hib disease. In the 1964-1965 rubella (German Measles) epidemic, there were 12.5 million cases of rubella. Of the 20,000 infants born with congenital rubella syndrome, 11,600 were deaf, 3,580 were blind, and 1,800 were mentally retarded as a result of the infection. In 1999 (after vaccination), there were 238 cases of rubella and 8 cases of congenital rubella. Before 1963, more than 3 million cases of measles and 500 deaths from measles were reported each year. More than 90% of children had measles by age 15. In 1999 (after vaccination), there were 86 cases of measles. In 1952, polio paralyzed more than 21,000 people. In 1998 (after vaccination), there were no cases of polio. In the early 1940s, there was an average of 175,000 cases of pertussis (whooping cough) per year, resulting in the deaths of 8,000 children annually. In 1999 (after vaccination), 6,031 cases of pertussis were reported. In the 1920s, there were 100,000 to 200,000 cases of diphtheria each year and 13,000 people died from the disease. In 1998 (after vaccination), there was only one case of diphtheria in the United States. As a result of the high level of immunization in the United States these diseases have declined to near zero.

Without protection from vaccines, the vaccine preventable diseases that have nearly been eliminated are likely to return to this country. Children who are not vaccinated against measles are up to 35 times more likely than immunized children to catch the disease. Ten years ago during a 3-year measles epidemic from 1989 to 1991, state health departments in the United States reported 55,622 measles cases, 11,251 hospitalizations, and 125 deaths. An investigation has shown that where this epidemic occurred, as few as 50% of preschool-aged children had received the measles vaccine. Thousands of children and adults will become sick, some will have long-lasting health problems, and some will die. Many other countries do not have the same levels of immunization that we have achieved in the United States and they continue to have disease outbreaks. Therefore, we must all remain protected by vaccines because dangerous diseases largely under control in the United States are only a plane ride away.

Vaccines are very safe and getting safer and more effective all the time as a result of medical research and ongoing review by doctors, researchers, and public health officials. Vaccines must meet the strict safety standards of the Food and Drug Administration (FDA) to ensure that they are safe and effective before they are approved. Scientific research and experience have shown that serious adverse effects from vaccines are extremely rare. The chance of serious complications from the diseases that vaccines prevent is many times higher than the chance of complications related to vaccines. As with all medicines, vaccines carry some element of risk. Doctors and public health professionals consider the balance of benefits and risks before recommending any vaccine. This balance is always subject to new information and can change when diseases are controlled or eradicated, or when there is new evidence about a vaccine or a vaccine-preventable disease that calls for a change in recommendations.

A 19-month-old child received nine immunizations in 2000 because she was behind in the recommended childhood immunization schedule. She had an underlying mitochondrial disorder. Mitochondria are the powerhouses of our cells, and mitochondrial disorders are extremely rare. She subsequently developed neurodegeneration, including some signs of autism spectrum disorder. The US Court of Federal Claims has agreed to pay the family from a federal fund that compensates people injured by vaccines.

The detailed investigation of this child with an underlying mitochondrial disorder may provide an important clue to understanding why rare complications occur with some vaccines. Moreover, future investigations might help identify a means to screen for such disorders, although because there are many different mitochondrial disorders and testing is invasive and expensive, screening is difficult. Other children with encephalopathy following vaccines have been compensated through the Vaccine Injury Compensation Program. What attracted public attention to this case was that it had been submitted as a test case by petitioners seeking compensation for children with autism following exposure to thimerosal (mercury) containing vaccines. The decision to award compensation in this case has nothing to do with the thimerosal that may have been present in the vaccines that the child received (in 2000, only two of the five vaccines this child received would have contained thimerosal; the others were already thimerosal free). The underlying mitochondrial dysfunction disorder in this case predisposes to neurodegeneration following significant stresses associated with infections, and possibly the multiple vaccines that this girl received. After the decision was made to award compensation, the case was withdrawn as a test case. Additional research is needed to determine if other children with autism, especially those with the regressive forms of autism, have the same or similar underlying mitochondrial dysfunction disorders.