Uptake of free vaccinations in US varies depending on ethnicity and income, says study

The uptake of free vaccines for children in the United States varied significantly depending on the relative income of different ethnic and racial groups, according to research by academics from City University London and National University of Ireland, Galway.

The study, which is published in the February issue of the journal Health Affairs, found that the introduction of the US Government-funded Vaccines for Children (VFC) intervention significantly improved the number of black and Hispanic children vaccinated relative to white children.

It also found that when it came to vaccinations among black families the income-related disparity between poor and rich families increased with vaccination rates rising more for high income families, while for Hispanics the discrepancy between the two decreased.

While the impact of the VFC programme has long been known due to the reduction of financial barriers, this is the first study to show how income can affect uptake across ethnic and racial groups.

In the United States alone, it is estimated that childhood vaccinations will prevent an estimated 322 million bouts of illness and 732,000 deaths over the course of the lifetimes of children born between 1994 and 2013, who benefit from the Vaccines for Children (VFC) program.

Specifically, the VFC program has improved access for children who are uninsured, whose insurance fails to cover vaccinations, who have Medicaid, or who are American Indian or Alaskan Native.

Speaking about the study, Dr Brendan Walsh, Research Fellow in the School of Health Sciences at City University London, said:

"We found that while racial and ethnic disparities in vaccinations were large at the beginning of the VFC program, vaccination rates across ethnicities have narrowed considerably, which is to be welcomed.

"Prior to the vaccine program, children from poorer, often non-white families had lower vaccination rates and higher rates of vaccine-preventable illnesses than those who were white, more well-off, or both. We also found that the reductions in disparities over the operation of the VFC program did not occur evenly over time, across vaccines, or among different groups."

Analysing data from the National Immunization Survey between 1995–2013 which included 342,062 children aged 19–35 months, the team found that at the beginning of the vaccine program, high-income white children were more likely to be vaccinated relative to their black and Hispanic peers. However, the latest period's vaccination rates among high-income children were similar, regardless of race. The highest uptake of MMR and polio vaccinations was seen among high income black children in 2011–13.

Among white children, differences in vaccine uptake rates have decreased overtime between high- and low-income children, halving for MMR and polio although remaining similar for Diphtheria, Tetanus, Pertussis (DTaP). Among black children, vaccination rates among high-income families increased at a much greater rate than that observed for low-income families. The largest increase in overall vaccination rates over time was observed among low-income Hispanic children.

Dr Walsh said: "We saw that low-income Hispanics increased uptake of virtually all vaccines to a greater extent, and in a more sustained manner over the duration of the vaccines program, than was the case among the other low-income groups.

"It is unclear whether these changes related to health promotion activities, increased public awareness associated with disease outbreaks, or changes in other factors seemingly unrelated to the value of vaccines for children. What is clear is that only a more thorough investigation of the changes in other factors that coincided with changes in vaccine uptake will provide a fuller understanding of the contribution of the VFC program to the increases in uptake and reductions in disparities. Failure to explore such patterns and seek a fuller explanation for the patterns of uptake observed not only means that valuable insights may be missed that could inform policy."