Understanding Childhood Vaccinations Rates: Turning Data Into Insights with Azara DRVS

Background

Benjamin Franklin once said: “An ounce of prevention is better than a pound of cure”. There are few better examples of this than the invention of vaccines, and the impact they’ve had on human health worldwide. For example, according to the Centers For Disease Control (CDC), the recommended 2-dose course of the measles, mumps and rubella (MMR) vaccine is 97% effective against measles and rubella as well as 88% effective against mumps[1]. The widespread adoption of the measles vaccine eventually led to the disease’s elimination in 2000 within the United States[2]. Another example is the polio vaccine (IPV), which has shown at least 99% effectiveness after only 3 doses (current recommendations are 4 doses by age 6)[3]. Because of this effectiveness, and its widespread adoption, polio has been considered eradicated in all of North and South America since 1994[4].

Although vaccines continue to be administered into adulthood, the vast majority are recommended before age 2. This early vaccination intervention “teaches” an infant’s immune system how to protect itself from these often deadly diseases.

The Measure

Vaccinations are critical to a child’s health. Because of this, HRSA requires all Federally Qualified Health Centers (FQHCs), as part of their UDS submission, report how many of their eligible patients are fully vaccinated by age 2. The Childhood Immunization Status eCQM CMS177 measure definition outlines the specific criteria that must be met for an eligible child to be included in the numerator of the measure. These specific requirements are detailed and extensive, but in general require:

• 4 DTaP vaccines, between 42 days and 2 years after birth
• 3 IPV between 42 days and 2 years after birth
• 1 MMR vaccine on or between the first and second birthdays
• 3-dose series Hemophilus Influenze B (HiB) vaccines between 42 days and 2 years after birth (or a 4-dose series, in lieu or in concert with, a 3-dose series)
• 3 Hepatitis B Vaccines within 2 years of birth
• 1 Varicella Zoster Vaccine (VZV) between the first and second birthdays
• 4 Pneumococcal Conjugate vaccines between 42 days and 2 years after birth
• 1 Hepatitis A vaccine between the first and second birthdays
• 2, 2-dose Rotavirus Vaccines between 42 days and 2 years after birth, or 3, 3-dose Rotavirus Vaccines between 42 days and 2 years after birth
• 2 Influenza Vaccines between 180 days and 2 years after birth, or 1 Influenza Vaccine between 180 days and 2 years after birth and 1 Life Active Influenza Vaccine (LAIV) administered on the patient's second birthday

These requirements almost exactly mirror recommendations by the CDC and the American Academy of Pediatrics and are very familiar to healthcare professionals who regularly treat children. Yet, the rates for this measure have been steadily declining in the past few years.

Looking at HRSA-provided measure results for all FQHCs and look-alike centers from 2021-2023 we see not only that results declined year over year, but they were poor (<40%) to begin with.

Given the importance of children having proper vaccinations early in life, why would we see such low overall results? To help answer this question, or at least provide more perspective, we can turn to Azara DRVS.

Analysis

The immunization measure is date sensitive and requires that all component vaccinations be completed by age 2. If even a single required dose is missed or is overdue by one day, that patient will not count in the measure numerator and reduce the overall result.

Thankfully, DRVS has a set of measures corresponding to each of those individual components. By looking at each of these individual “sub-measures”, we can get a peek under the hood to see what individual vaccinations are not meeting criteria and thus driving the overall measure result downward.

To do so, we looked specifically at annual measure data for 2023 from DRVS, and saw some interesting results:

The above chart shows what appears to be three “groupings”. The left-most 5 vaccines have the highest completion rate. Although perhaps not as high as experts may like, they are at or above 80% and not contributing much to the low overall measure results.

The next 4 vaccines, DTaP, HIB, pneumococcal, and rotavirus, have results that are about 15 percentage points less than the first 5 (MMR, Polio, etc.). Why that is the case, however, isn’t entirely clear from this data. Although the rotavirus and pneumococcal vaccines are somewhat newer (if you consider 20-25 years to be “new”), DTaP and HIB vaccines have been available for much longer.

Finally, in the third “grouping” we see that the annual flu vaccine has the lowest results of all the individual vaccine measures.

If even a single required dose is missed or is overdue by one day, that patient will not count in the measure numerator and reduce the overall result.

Influenza

The flu vaccine, being the lowest of the individual measures, is likely the majority reason for the low overall measure results. But, why would the flu vaccine be such a challenge? It is different from the other vaccines because it is reformulated each year to match what experts believe will be the most common strains in the upcoming flu season. Is the window of availability for the vaccine a challenge for some patients to be able to receive it?

To shed some light on these questions, we took a sample of DRVS-enabled centers then looked at what the data showed in terms of numbers of vaccines given.

We focused on patients who did not meet the specific flu measure in 2023 to see whether they received just 1 vaccination and simply missed a second subsequent one, or if those patients did not have any flu vaccinations at all. The visual below shows these results, and they are startling:

About 80% of patients in this sample did not have any record of an influenza vaccine at all, while the other 20% had only a single flu shot before their 2^nd birthday. This seems to indicate that the issue is not likely to be caused by well-child visits failing to coincide with the vaccine’s availability, but rather something else. Is there a higher vaccine hesitancy that is specific to flu shots? Is it possible that flu shots are being administered elsewhere and not reflected in the EHR? Or perhaps there is a sentiment that the flu isn’t “that bad” and thus vaccinating for it is less important? Unfortunately, those answers are likely not found in the data, but rather at the point of care.

Summary

The Childhood Immunization measure continues to be a challenge for all FQHCs, as UDS shows a steady decline in recent years. There are myriad possible reasons why we may be seeing this trend: vaccine hesitancy, access to care, and so on. However, by utilizing the individual vaccine measures available in DRVS, practices have the capability to explore individual vaccine rates. Those insights can then be used in a variety of ways to support increasing measure compliance: outreach, education, community vaccine clinics, and more.

[1] https://www.cdc.gov/vaccines/vpd/mmr/public/index.html#how-well-mmr-works

[2] https://www.cdc.gov/measles/about/history.html#cdc_generic_section_3-measles-elimination-in-the-united-states

[3] https://www.cdc.gov/polio/vaccines/index.html

[4] https://www.mayoclinic.org/diseases-conditions/history-disease-outbreaks-vaccine-timeline/polio