News & Views: What Do this Year’s Vaccine Coverage Measurements Tell Us?

Globally and nationally, public health officials measure vaccination rates at regular intervals to monitor progress and areas of vulnerabilities. In July 2018, the World Health Organization (WHO) published a global update of vaccination coverage for children. More recently, the Centers for Disease Control and Prevention (CDC) published the results of the 2017 National Immunization Survey (NIS-Child) that assesses vaccination coverage among children in the U.S. between 19 and 35 months of age. In addition, they released vaccination rates for children entering kindergarten during the 2017-2018 school year.

Each of these reports is rich in data and provides an excellent understanding of the state of vaccination. We encourage you to review each, particularly as it relates to your geographic and technical interest related to vaccinations. However, we wanted to draw attention to some of the numbers, what they tell us, and actions to consider.

85 percent of children around the world had at least one dose of measles vaccine.

What this number tells us

Measles is one of the most contagious diseases. One infected person can spread the disease to between 12 and 18 other people who are susceptible. Herd immunity of greater than 90 percent is required to stop transmission.

The vaccine is effective. After one dose, 93 of 100 people will be protected, and this increases to 97 of 100 following a second dose.

However, in some parts of the world, even some parts of the U.S., herd immunity thresholds are not sufficient to stop transmission of measles:

• Recent global data found that only 85 of every 100 children in the world have received one dose of measles-containing vaccine.
• In the U.S., 11 states had coverage rates lower than 90 percent.
• Kindergarten data are based on two or more doses of MMR. When comparing the kindergarten cohort with their historic NIS-Child results (2014), in 2 of 10 states, measles vaccine coverage remains below 90 percent in kindergarten children.

Actions to consider

During outbreaks, the majority of infected individuals are not vaccinated. Therefore, it is important to encourage measles vaccination at every opportunity and to ensure that families delaying or withholding MMR understand the risk in the context of these data.

Seven percent of uninsured children in the U.S. received no vaccines compared with 1 percent of privately insured children.

What this means

Much of the media coverage related to the NIS-Child data focused on the increase of completely unvaccinated children from 0.3 percent in 2001 to 1.3 percent in 2017. While this number is concerning, it is important to take a closer look at the data. Specifically, 7 percent of uninsured children received no vaccines compared with 1 percent of privately insured children. Similarly, when looking at where completely unvaccinated children lived, significantly more lived in rural areas compared with metropolitan areas (1.9 percent versus 1.0 percent, respectively).

Because uninsured and underinsured individuals can receive vaccines at no cost through the Vaccines for Children (VFC) program, these data suggest that barriers other than cost are contributing to lower rates of vaccination.

Further, the significant difference in where unvaccinated children reside suggests that the availability of providers giving vaccines, specifically pediatricians, may play a role in coverage rates.

Actions to consider

Because the VFC program ensures that all children should be able to afford vaccinations, immunization programming and outreach activities should evaluate contributing barriers to coverage in areas with high rates of non-vaccinators. While some missed vaccinations are likely due to choice, other factors are also contributing to the most recent data. Ensuring access to vaccination providers, reducing missed opportunities, and promoting timely immunizations could increase vaccination coverage.

1.5 million child deaths could be averted every year with increased vaccination rates.

What this means

While 85 percent of children receive some vaccines, the WHO estimates that increasing immunization rates could avert 1.5 million deaths annually. Almost 20 million children throughout the world did not receive a three-dose series of DTP vaccine. Sixty percent of these children resided in 10 countries: Afghanistan, Angola, the Democratic Republic of the Congo, Ethiopia, India, Indonesia, Iraq, Nigeria, Pakistan and South Africa.

Actions to consider

Efforts to immunize children in countries such as those listed above should remain a priority. Those working in other countries should ensure that patients who travel and those who opt out of vaccinations understand that the world is small when it comes to the spread of infectious diseases. While a disease may be a concern today, it could be an exposure or outbreak tomorrow.