By the time they are two years old, most children from middle and upper-income families have been vaccinated against polio, mumps, measles, rubella and tetanus. But many low-income children–too many, according to the Center for Disease Control (CDC) and the Vaccines for Children Program– have not. A new study examining the results of the U.S. National Immunization Survey carried out between 1995 and 2007 showed “significant disparities in timely vaccination coverage… between low- and high-income children for all childhood vaccines and nearly every birth cohort born between 1994 and 2004.” A low-income household is defined as having an annual income of 133 percent or less of the federal poverty level, and the survey involved 232,318 children in that bracket. These children were compared with children in high-income households (defined as have 400 percent or more of the federal poverty level), who were tracked between 1994 and 2004.

The good news is that more children from lower-income families are receiving vaccinations than in previous years, with the help of organizations like the Vaccines for Children Program, which was founded in 1994. The program was established in response to a measles resurgence from 1989 to 1991, and provides low-cost and no-cost vaccines to qualifying children. The report states, “In our analyses, we found that among low-income children, timely vaccination coverage rates for all vaccines exceptHib [Haemophilus influenza type b] have increased significantly between consecutive cohorts born after the measles resurgence.”

With the exception of the DTap-DTP vaccine (which protects against diphtheria, tetanus and whooping cough [pertussis]), where the disparity between rich and poor who had been vaccinated rose 0.4 percent, and for polio, where there was no change, the gap between low- and high-income children is decreasing. Examples include vaccines like MMR (for which the disparity has declined by 0.3 percent), hepatitis B (0.3 percent decline), and varicella, also known as chickenpox (0.5 percent decline).

The CDC considers having the following vaccinations by age 19 months ‘timely’: diphtheria, tetanus, pertussis, polio, measles, mumps, rubella, Haemophilus influenza type b, hepatitis B and varicella. The only disease for which timely immunizations did not increase among low-income children was Haemophilus influenza type b, or the Hib, which is not the flu, as the name may suggest. In fact, Hib is a serious bacterial disease, and, before the vaccine was invented, was the number one cause of meningitis.
Overall, the report yields a mixed bag of results. While progress has been made, there are still clear socioeconomic disparities between who is vaccinated and who is not. The report suggests, to further reduce the gap, changes such as “improving health care providers’ reminder/recall systems, implementing educational interventions that address barriers to vaccination and increasing parents’ awareness of the Vaccines for Children Program.” When at the doctor’s office with their children, parents should ask about their child’s vaccination history and find out if the doctor thinks certain vaccines should be administered during the visit. Medical professionals hope it does not take an emergency like the recent swine flu outbreak to spur parents to seek vaccinations for their children.

“On the whole, low-income children are catching up,” said Dr. Peter Belamarich, a pediatrician at Children’s Hospital of Montefiore in New York City. “There’s more work to do, but we’re having success on the whole in increasing vaccination rates,” he said.