Question: Can too many vaccines overload a young immune system?
Some 40 percent of parents recently surveyed said they worry about too many vaccines given in a single doctor's visit, according to CDC findings presented earlier this year at the National Immunization Conference in Dallas. Judy Van de Water, Ph.D., is an immunologist at the University of California, Davis, who is directing an investigation, funded by the National Institutes of Health (NIH), into the potential environmental risk factors that may be behind the rise in autism. "A healthy child should do fine with our current vaccination schedule," she says, "but you can't always know how robust a child's immune system will be prior to vaccination."
Some experts suggest that some children who develop autism have faulty immune systems. A 2008 study published in the journal Autism Research compared levels of immunoglobulin (antibodies that play a role in immunity) in normally developing children with the levels in children with autism. It showed that children with autism had lower levels of immunoglobulin, suggesting "an underlying defect in immune function." A 2009 study published in the journal Brain, Behavior and Immunity did a similar comparison and found abnormalities in the "natural killer cells" (the big guns of the immune system) of children with autism spectrum disorders, which "may predispose them to the development of autoimmunity and/or adverse neuroimmune interactions during critical periods of development."
"Since some vaccines are designed to mimic infections," Van de Water says, "you can imagine how sick you could be if you get nine at once and your immune system is not working optimally -- for any number of reasons." She and her team are developing a heel-stick test that will determine the health of a child's immune system before immunization, but it's still years away from FDA approval. In the meantime, if your child has a bad response to an early vaccine -- acting very lethargic for more than 24 hours and running a fever of 100 degrees Fahrenheit or higher -- Van de Water suggests that it may sound a warning about future vaccinations. For other signs of how the state of a patient's immune system impacts immunization, visit the CDC website (cdc.gov).
Facts: "Just by breathing air, eating food and sticking toys in their mouths, babies and kids encounter many more foreign substances every day than the ones in their vaccines," says Martin G. Myers, M.D., a pediatrics professor at the University of Texas Medical Branch at Galveston and author of Do Vaccines Cause That?! A Guide for Evaluating Vaccine Safety Concerns. "Consider that a baby's immune system is assaulted with billions of foreign substances within seconds of birth, whereas all the childhood vaccines put together have far less antigens."
As Brown notes, vaccines today are not only highly purified, packing a bigger punch using less vaccine material, but the material itself is safer. "With smallpox, the first successful vaccine ever developed, your body would mount an immune response to a tiny bit of a real germ to prepare the body for exposure to an actual infection," she explains. With advanced medical technology, most of today's vaccines rev up your immune system to make antibodies (like smart bombs with memory) for the germ's signature or calling card -- not the germ itself. This way, if your body does encounter the germ, it will recognize its calling card and launch the smart bombs to fight it off.