The most common reactions are fever, soreness at the site of the shot, and irritability. Compared to the diseases these vaccines inoculate against, however, the reactions to the shots are mild. Before vaccines became widely available, diseases like measles, mumps and whooping cough were common in childhood, and thousands died or were left blind, deaf or brain-damaged by them. Today, vaccines have totally or nearly eradicated several diseases such as smallpox, polio, diphtheria, and Hib infections, according to the national Centers for Disease Control and Prevention. In some inner city areas, only 10 percent of children have been properly immunized.
Some people blame the low rates on inconvenience.
There are nine diseases to vaccinate against, with as many as 15 doses in about five visits to the doctor before a child's second birthday. Others point out that parents are required to have children vaccinated only before enrolling them in school or day care. But babies and toddlers not in structured day care are most likely to miss their shots. The cost of vaccines may be another factor in low immunization rates. Only half of health insurance plans cover childhood vaccines, though many public health departments offer them free or at a reduced fee based on income.