Vaccines continue to be the most common topic of conversation in pediatricians' offices. Discussions regarding the potential complications from "baby shots" have been front and center in the media, causing concern and anxiety among parents of infants and toddlers.

Any mention of standard vaccinations generates the same three questions: Are vaccines necessary? Are vaccines safe? Do vaccines cause autism?

In many ways, routine vaccination has become a victim of its own success. In the last 20 years, we have vaccinated more than 100 million American children. Immunization rates are at an all-time high in the United States, and epidemic disease is at an all-time low.

We are now more than a generation away from the last epidemic. The vast majority of today's parents, having never experienced these horrific diseases, have no understanding of the suffering involved when someone contracts polio, measles, tetanus, diphtheria, pneumococcal meningitis, haemophilus meningitis, mumps or hepatitis. They ask why we continue to immunize kids against nonexistent disease.

On the surface, it may seem appropriate for parents to "protect" their children from the implied perils of vaccines by refusing to have them vaccinated. The reality, however, is quite different. Vaccines work by protecting individuals when they are exposed to specific germs. In protecting individuals, they protect the community as well.

If a very high percentage (more than 90 percent) of children are immunized, there is group, or what we call in medicine "herd," immunity. (For some, vaccination doesn't work or can't be administered, as in cases of immune deficiency or cancer patients.) Given our mobile society, each of us may be only a plane ride away from any one of these diseases, and we must depend on one another for much of our protection.

These are not insignificant issues. Haemophilus influenza (Hib) is just one example. Before the haemophilus influenza vaccine became available, 20,000 children under age 5 in the United States contracted Hib meningitis each year; 1,000 of them died. Today, we rarely encounter this disorder. However, there is currently a small outbreak of measles in San Diego, and as physicians, we worry that, if vaccination rates fall, the entire country will be at risk.

As with all medications, there can be side effects and long-term complications from vaccines. At times, they can cause minor illness, such as the aches, pains and fevers associated with the vaccine for influenza. Varicella vaccination can result in very mild cases of chicken pox.

We seek to avoid possible complications through close surveillance and scrutiny of vaccines. For example, in the United States, live polio vaccine was replaced by a "killed" vaccine product to avoid the rare case of polio (less than one per year) related to vaccination. A number of years ago, Rotavirus vaccine was introduced to prevent diarrhea, but was removed from the market a few months later when it was found to play a role in intestinal blockage.

More recently, there has been speculation surrounding a relationship between vaccines and autism. Autism or ASD (autism-spectrum disorders) are a group of severe developmental disorders characterized by detachment. The incidence of autism has risen over the last two decades; nearly one in 150 children now carries a diagnosis of an autism spectrum disorder. This apparent increase in cases can be related to many factors, including a real increase in incidence, a broader classification system, increased societal awareness, or a combination of the three.

Autism is most commonly diagnosed during a period when children receive the majority of their vaccines. Vaccines are given to young children, because they are most at risk and in need of protection. Although autism-spectrum disorders often appear during the same time period as the vaccination process, intensive scientific study has revealed no causal relationship between the two factors. To stop vaccinating children, based on unscientific speculations and conclusions, would put tens of thousands of children in harm's way.

As we move forward, we must continue to protect our children and ourselves through active immunization programs. We must also press on with vigorous efforts to more clearly define autism-spectrum disorders, determine their causes and initiate effective preventions and interventions. If you are worried about vaccines, make sure you discuss your concerns with your pediatrician.


Dr. Edward Bailey is chief of pediatrics at NSMC North Shore Children's Hospital and is on staff at Massachusetts General Hospital for Children. He is married and the father of three. You can contact him at

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