Vaccine Safety

What Happens When We Don't Vaccinate?

Parents educating themselves about childhood immunizations sometimes ask this question. We found a good answer at the CDC:

Although vaccines have dramatically reduced the number of people who get infectious diseases and the complications these diseases produce, the viruses and bacteria that cause vaccine-preventable diseases and death still exist. Without vaccines, epidemics of vaccine-preventable diseases would return. Here is an idea of the effects of vaccinating and not vaccinating.


Prior to vaccination, between 13,000 and 20,000 polio cases of paralytic poliomyelitis were reported each year in the United States.

In 1996, because of a global effort to eliminate the disease through vaccination, there were only 3,500 documented cases of polio in the world. Wild polioviruses have been eliminated in the entire Western Hemisphere.

If we were to discontinue polio vaccination in the United States, immunity to polio would decline, leading to the risk of polio epidemics similar to those that occurred in the past.


Before measles immunizations were available, nearly everyone in the United States got measles. There were about 3-4 million cases each year. An average of 450 measles-associated deaths were reported each year between 1953 and 1963.

In industrialized countries, up to 20 percent of people with measles are hospitalized, and 7-9 percent suffer from complications such as pneumonia, diarrhea or ear infections. Some people with measles develop encephalitis, and 1:1,000 people with measles die.

Widespread use of the vaccine has led to >95 percent reduction in measles.

Measles still occurs throughout the world, and is frequently imported into the United States. In 1995, there were 1.1 million deaths worldwide from measles. If vaccinations were stopped, 2.7 million deaths could be expected.

Stopping measles vaccination would probably lead to massive epidemics similar to those that occurred in the pre-vaccine era. Between 1989 and 1991, the number of reported measles cases rose sharply, with >55,000 cases, 11,000 hospitalizations and 120 deaths reported. The major cause of the outbreak was low rates of vaccination among preschool children.

Haemophilus influenzae type b meningitis

Before Hib immunization, Hib was the most common cause of bacterial meningitis in U.S. infants and children. Before the vaccine, there were about 20,000 invasive Hib cases annually. About two-thirds were meningitis. Up to 8,000 cases of life-threatening invasive Hib disease – bacteremia, pneumonia or epiglottitis – also occurred annually. 1:200 U.S. children younger than 5 got Hib disease. Hib meningitis killed 600 children each year, and left many survivors with deafness, seizures or mental retardation.

Since the introduction of the vaccine in 1987, the incidence of Hib has declined by 97-99 percent. Fewer than 10 fatal cases of invasive Hib diseases were reported in 1995.

Without vaccination, this disease would likely cause the same amount of disease and deaths that it caused before the vaccines were developed.


Before pertussis immunizations were available, nearly all children developed pertussis. In the United States, prior to pertussis immunizations, between 150,000 and 260,000 cases of pertussis were reported each year with up to 9,000 pertussis-related deaths.

Pertussis can be a severe illness, resulting in prolonged coughing and vomiting spells that can last for weeks. These spells can make it difficult for a child to eat, drink and breathe. In infants, it can cause pneumonia and lead to brain damage, seizures and mental retardation.

During the 1970s, widespread concerns about the safety of pertussis immunization led to a rapid fall in immunization levels in the United Kingdom. Within several years, a series of pertussis epidemics occurred; >100,000 cases and 36 deaths due to pertussis were reported in one epidemic in the mid-1970s.

Concerns over vaccine safety have been addressed with the newer acellular pertussis vaccine, which is effective and is associated with fewer and milder adverse reactions than the whole-cell product.

In Japan, pertussis vaccination coverage fell 80 percent in 1974 to 20 percent in 1979. An epidemic occurred in 1979, resulting in >13,000 cases and 41 deaths.

If we stopped giving pertussis vaccine in the U.S., we would experience a massive resurgence of disease. A recent study found that, in eight countries where immunization coverage was reduced, incidence rates of pertussis surged to 10-100 times the rates in countries where vaccination rates were sustained.


While rubella is usually mild in children and adults, up to 90 percent of infants born to mothers infected with rubella during the first trimester of pregnancy will develop congenital rubella syndrome, resulting in heart defects, cataracts, mental retardation and deafness.

In 1964-65, before U.S. rubella immunization was used routinely, there was an epidemic of rubella that resulted in an estimated 20,000 infants born with CRS, with 2,100 neonatal deaths and 11,250 miscarriages. Of the 20,000 infants born with CRS, 11,600 were deaf, 3,580 were blind and 1,800 were mentally retarded.

If immunity to rubella were to decline, rubella would return, resulting in pregnant women becoming infected and giving birth to infants with CRS.

The above information covers five of the 10 vaccine-preventable diseases against which children are routinely vaccinated. Stopping vaccination would also cause major increases in diphtheria, tetanus, hepatitis B, varicella and mumps.


Important disclaimer: The information on is for educational purposes only and should not be considered to be medical advice. It is not meant to replace the advice of the physician who cares for your child. All medical advice and information should be considered to be incomplete without a physical exam, which is not possible without a visit to your doctor.

Immunizations stop
disease from spreading.

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doctor to see if you could benefit.