Vaccines, also called immunizations, are designed to boost your child’s immune system against specific infectious agents, protecting him from serious and sometimes life-threatening diseases.
Vaccines come in many varieties. Some are lab-manufactured replicas of a piece of a bacterium or virus. These are called recombinant vaccines. Others are made by attaching proteins to parts of a bacterium. These are called conjugated vaccines. These two methods of manufacturing vaccines use only small pieces — or even replicas of small pieces — of organisms that cause infections. The recipient is not exposed to the entire bacterium or virus, just to one little part of it. This gives the immune system the illusion that the body is infected when it really isn’t.
A few vaccines are produced by altering an entire bacterium or virus — using heat to denature its proteins, thereby rendering it inactive. These are called inactivated or killed vaccines. Finally, some vaccines are made from a living virus. The virus is weakened, so that when it is given in the form of a vaccine, it cannot cause a full-blown illness. These are called live-attenuated vaccines.
All four kinds of vaccines work by tricking your child’s immune system into thinking the body has been exposed to a true bacterial or viral infection. The immune system then makes the appropriate antibodies to fight off that particular infection. Therefore, when the child is exposed to the true virus or bacterium, the body has been primed, giving the immune system memory that will provide rapid antibody production.
Over the past few decades, the number of vaccines recommended by the Centers for Disease Control (CDC) and the American Academy of Pediatrics (AAP) has increased significantly. The vaccines are listed on an immunization schedule that is revised regularly. Most schools require completion of the schedule prior to entry. Although these vaccines are strongly recommended, they are not required by law.
Many parents have raised concerns about the long-term effects of vaccines on children’s health and development. Their concerns range from the use of preservatives in vaccines to the administration of multiple vaccines during one doctor’s visit. For some parents, weighing the risks and benefits has complicated what was, in the past, a simple rite of passage.. Although some of the vaccines described here are routinely administered before a child’s first birthday, booster doses often are given in the toddler years. Therefore, all of the vaccines listed on the AAP vaccine schedule are included here.
Given the recent attention focused on preservatives used in vaccines — specifically, the mercury-containing compound thimerosal—this topic deserves an extra note. In 1999, the AAP voted to remove thimerosal from the routine childhood vaccines. Since 2001, each vaccine listed on the recommended schedule has been available thimerosal-free. Although there are still some vaccines produced using thimerosal as a preservative, almost all of the vaccines stocked in pediatric offices are thimerosal-free.