Last month, the National Committee for Quality Assurance released some interesting numbers on childhood vaccination rates. They found that childhood vaccination rates among children with commercial insurance plans (the kind you would get from an employer or purchase yourself) fell around 4%. Vaccination rates increased among children receiving Medicaid, the government health care plan for the poor.
The NCQA cited vaccine myths as a possible reason. Wealthier families---those than can afford private insurance---may have more access to information, including bad information. I have an additional hypothesis. I just trotted across the hall to the pediatric clinic and found out that Medicaid---at least in this state---mandates certain quality practices, including the administration and recording of vaccinations. Most commercial plans are only beginning to implement these sorts of programs.
Whatever the cause, the trend is worrisome. Depending on factors such as geographic location and schooling, wealthy kids may be increasingly free-loading on poorer kids, benefiting from herd immunity without participating in the (minimal) risks. This is ethically unpleasant behavior, and is bad for public health.