Vaccinations have tamed, and in some cases eliminated, many childhood illnesses. The immunizations only work, however, when people get the needed shots. Nearly all pre-schoolers in Maine and most other states get the vaccines they need, but too many teens are not getting shots to prevent diseases such as meningitis, mumps and chickenpox. Requiring vaccination for school attendance has helped boost vaccination rates, but more public education is needed to remind parents that dangerous illnesses can be avoided with immunizations.

Chickenpox is one example. In 2003, the Legislature approved a program to immunize all Maine schoolchildren against the itchy illness in five years to bring the state in line with much of the rest of the nation. In 2004, those entering kindergarten and first grade had to show proof of vaccination or proof of a parental objection to the immunization.

Each year additional grades need proof of vaccination of immunity due to already having had chickenpox. In 2007, proof of vaccination will be needed for all K-12 students.

Last year, many districts began strictly enforcing the vaccination requirement and dozens of schools were barred from school until they got the shots.

According to the Health Plan Employer Data and Information Set, about 30 percent of New England adolescents go without the immunizations they need. Although state and federal agencies collect lots of data on immunization rates among toddlers and kindergarteners, there is little information available on teenage vaccination rates.

A decade ago, immunizations were given before children entered school and only a tetanus shot was needed for older students. Now they need additional shots to prevent chickenpox, measles, meningitis, mumps, rubella, Hepatitis B and diphtheria.

A recent study, published in Pediatrics magazine, found that such vaccinations saved health care dollars. In 1993, two years before the U.S. government licensed the vaccine for routine use in early childhood, nearly 14,000 Americans were hospitalized each year for chickenpox-related complications at a cost of $161 million. In 2001, the hospitalizations were down to 3,729 with a cost of $66 million, according to the researchers at the University of Michigan.

On the reverse side, the United Kingdom had an outbreak of measles in 2003. Vaccination rates had fallen below 80 percent and the number of measles cases had tripled since 2001.

Dora Anne Mills, the director of the Maine Center for Disease Control, emphasizes that vaccines are safe. Proteins that are the main ingredients of immunizations are purified more than ever before and many shots are available in preservative-free formulations. Thimerosal, which some fear is linked to autism, is now rarely found in more than trace amounts in childhood vaccines.

Vaccinations work, but only if children and teenagers receive them.