Under current regulations, state laws require vaccinations for all children enrolling in kindergarten. Today, the U.S. enjoys the highest immunization rate ever: 77% of children are completely up-to-date on their recommended doses and those remaining who are not fully up-to-date are missing just a few shots by the first day of school.

Meanwhile, since the 1980s, the number of vaccinations children receive has doubled, while autism diagnoses have tripled. And, last month the U.S. government - which has always stood by the safety of vaccines - acknowledged that a nine-year-old Georgia girl with a preexisting cellular disease experienced a worsening of her disease due to inoculations she received as an infant, which "significantly aggravated" the condition, resulting in a brain disorder with autism-like symptoms. Government officials won't say why they conceded this case, but did say those with pre-existing injuries can obtain compensation under the program if they establish that their underlying condition was "significantly aggravated" by a vaccine.

Despite the rules requiring students to be vaccinated, doctors can issue waivers to children whose compromised immune systems might make vaccines risky. All but two states allow waivers for children whose parents object to vaccines on religious grounds; 20 allow parents to opt out on philosophical grounds.

Meanwhile, since the 1930s, a mercury compound known as thimerosal had been included in some vaccines - but not the measles inoculation - as a preservative to keep the vaccines free of fungi and bacteria. Thimerosal is now known to do serious damage to brain tissue, especially in the brain tissue of children, whose brains are still developing. And, in 2001, a U.S. Food and Drug Administration (FDA) study revealed that a six-month-old receiving the recommended complement of childhood vaccinations was exposed to total levels of vaccine-based mercury that were twice as high as the amount the Environmental Protection Agency (EPA) considers safe in a diet that includes fish. By year-end 2001, thimerosal-free formulations of the five inoculations that previously included thimerosal - hepatitis B, diphtheria, tetanus, pertussis, and some versions of Haemophilus influenzae type b (Hib) - replaced the older thimerosal-containing versions of the vaccines. A drop in mercury exposure in fully immunized six-month-old babies from 187.5 micrograms to just trace amounts still found in some flu vaccines was realized.

Many parents have raised concerns over the government's handling of the vaccine controversy as well as the vaccine industry, which continued developing shots to the point where today's children receive up to 28 injections for 14 diseases, more than double the number required in the 1970s. And, now, parents are also beginning to object to the mandatory nature of the shots - and that a child's access to education is contingent on compliance with immunization regulations. Also, some parents question why children are being inoculated against rarely seen diseases, such as polio.

Most agree that there may be children with genetic predispositions or other underlying conditions that make them susceptible to being harmed by vaccines. The Georgia girl in the recent vaccine case is the first such documented child, but her story suggests there could be others.