Childhood Vaccinations -- Know the Routine
What every parent should know about the vaccines that keep kids safe from disease.

One hundred years ago, approximately half of all children born in the United States died by the age of 5, many of them from diseases that are prevented by vaccines today. By 1979, the dreaded smallpox had been wiped out entirely, thanks to a worldwide vaccination effort. Today, vaccines have nearly eliminated polio in the Western Hemisphere and have almost eliminated measles in this country.

With each vaccine developed, more lives are saved and millions of children are spared needless suffering. In recent years, a small but highly vocal group of people has been claiming that vaccines themselves may cause side effects worse than the diseases they're meant to prevent. Alarmist articles quoting these antivaccine factions may have led some parents and grandparents to wonder whether vaccines are worth the supposed risks.

"Scientists and physicians who work in the field of disease prevention, myself included, understand these concerns," says Neal A. Halsey, M.D., director of the Division of Disease Control and of the Institute for Vaccine Safety at the Johns Hopkins University's Bloomberg School of Public Health. "But we also understand that the issue of side effects is being raised primarily because we have the luxury of living in a time and place in which the risk of the major diseases has been reduced or eliminated. The reality is that vaccines are enormously safe and continue to offer the best protection against potentially serious illness. If we stopped vaccinating, the diseases would return."

How Vaccines Work

When a naturally occurring disease-causing pathogen, such as bacteria or a virus, enters your body, your immune system may produce antibodies to destroy that specific invader. If the same pathogen is encountered a second time, the immune system recognizes it and produces antibodies much more quickly, killing the pathogen before symptoms can develop. That's why someone who had a disease such as measles as a child is immune to the disease later.

Vaccines work by the same principle. "By being exposed to a small portion of the pathogen," explains Dr. Halsey, "the body is able to make antibodies to fight the disease without actually having to suffer the illness. The number of doses depends on the type and strength of the vaccine and how the body's immune system responds." For some vaccines, such as tetanus, periodic booster shots may be required to keep immunity high.

Vaccines occasionally cause temporary mild side effects, such as fever, muscle aches and swelling or discomfort at the injection site. Serious side effects are rare. To minimize fear and needless worry, parents and grandparents should ask for and read the Vaccine Information Statements (VIS) before their children and grandchildren are vaccinated or immunized. These statements explain the diseases, the relevant vaccines and what side effects, if any, might be expected.

The Seven Childhood Vaccines

Current guidelines call for children to receive a total of 23 doses of seven different vaccines protecting against 10 diseases. A table showing when they should be given appears at the end of this article. Dr. Halsey provides this run-down of the key points about each of those vaccines:

• Hepatitis B. Hepatitis B can lead to acute and chronic liver disease as well as liver cancer. There has been some controversy about giving the vaccine to children, mostly because of the myth that the disease is transmitted only by sexual contact or needle exchange. In fact, the disease can be spread through routine close contact with people living in the same household, and studies from other countries suggest that normal child-to-child play can spread infection. All children and adolescents should be immunized. Although rumors suggest that the vaccine may cause chronic illness, including multiple sclerosis or other demyelinating diseases, scientific studies have shown no such association.
  
  
• Diphtheria/tetanus/pertussis (DTP). All three of these diseases can be fatal, and because the organisms that cause them are still widely present, continued vaccinations and regular booster shots are highly recommended. The original whole-cell form of the vaccine, known as DTP, was reported to cause side effects in a small number of children, including high fever, seizures with fever and, rarely, other effects. (Careful investigation has shown that, contrary to rumors, there is no causal relationship between the DTP vaccine and sudden infant death syndrome, or SIDS.) The new DTaP vaccine uses a safer "acellular" form of pertussis, which is much less likely to cause side effects. DTaP has been shown to be just as effective as DTP for preventing illness and is now recommended for the five-dose series. Parents should specifically ask that their children receive the DtaP vaccine instead of the DTP vaccine.
  
  
• Haemophilus influenzae type b (Hib). Not to be confused with the "flu" influenza, the Hib bacterium causes potentially deadly meningitis, pneumonia and bacterial sepsis. Because of widespread use of the vaccine since the early 1990s, we are close to eliminating Hib as a childhood illness in the United States. The key to providing optimal protection is to make sure children are vaccinated as early as possible within the acceptable vaccination timeframe.
  
  
• Pneumococcal diseases. A highly effective vaccine has just been approved to protect infants against pneumococcal infections, which have been among the leading causes of meningitis in infants and children since the introduction of the Hib vaccine. The new vaccine also protects against pneumococcal blood infections and appears to decrease pneumonia and otitis media (a common form of middle-ear infection in children) due to the pneumococcus.
  
  
• Poliomyelitis. Although polio has been eradicated in the United States, it remains a serious threat in other parts of the world. International travelers can still bring the disease home, so it's important to immunize all children. Serious but rare side effects have been reported with the "live" oral form of the vaccine, including some cases of vaccine-induced polio, so only the safer, injectable form will be used for the four-dose series.
  
  
• Measles/mumps/rubella (MMR). Fewer than one child in 1 million who get this vaccine has a serious allergic reaction or other severe problem. British researchers recently disproved rumors of a link between the vaccine and inflammatory bowel disease or autism.
  
  
• Varicella (chickenpox). Although chickenpox is normally thought of as a harmless childhood disease, about 100 people die of chickenpox each year in the United States. Unless there is a contraindication to the varicella vaccine, all children should be immunized, and adults who did not have the disease as a child should be tested to see if they have acquired immunity. If not, vaccination is recommended because chickenpox can be far more serious in an adult than in a child.

Getting Better All the Time

Researchers are constantly looking for ways to improve vaccines and keep the public safe against diseases and vaccination side effects. To make vaccination less traumatic for children (and their parents), scientists are working to develop more combination vaccines that will deliver the same degree of protection with fewer injections. In the future, some vaccines may even be delivered by nasal spray, starting with an influenza vaccine that may become available soon.

On the downside, a new rotavirus vaccine, which had seemed so promising during test trials, was recently withdrawn because of the risk of an unanticipated side effect. The timely withdrawal was the result of an effective system to monitor vaccine safety.

 Childhood Vaccinations: Recommended Routine

Last Updated: 10/11/2002
The Johns Hopkins University 1996-2003.  All rights reserved.  This information is not intended to provide advice on personal medical matters, nor is it intended to be a substitute for consultation.