News & Views: Vaccines — Local? Societal? Both.

Vaccinations are local. Regardless of whether your trip to the “office” lands you in a clinic in rural America or a country in west Africa, you are likely to recall examples that demonstrate the diverse nature of local populations and perhaps even have experiences related to how that diversity affects vaccine acceptance and uptake. Unfortunately, the pathogens that cause vaccine-preventable infectious diseases do not respect borders or diversity of populations, so societal protection is at the mercy of local protection. As stated by Thomas Reid, “The chain is only as strong as its weakest link, for if that fails the chain fails and the object that it has been holding up falls to the ground.”

This reliance on local protection for its role in societal protection means that the work of understanding the beliefs and attitudes of one’s own patient or community population as well as local barriers to vaccination is critical. It also means that we need a contextual understanding of the state of societal protection for how it may affect our own communities. With this in mind, four recently published reports are worth reviewing for their contributions to this unbreakable bond between local and societal protection:

1. "Vaccination Coverage by Age 24 Months Among Children Born in 2019 and 2020 — National Immunization Survey-Child, United States, 2020–2022" (NIS-Child)
2. "Coverage with Selected Vaccines and Exemption from School Vaccine Requirements Among Children in Kindergarten — United States, 2022–23 School Year" (Kindergarten)
3. "CDC’s State of Vaccine Confidence Insights Report" (Rural vaccine confidence)
4. "Routine vaccination coverage – worldwide, 2022" (Global vaccine coverage)

The first two reports (NIS-Child and Kindergarten) offer a snapshot of U.S. vaccine coverage, including data by state and demographic. The third report, while focused on COVID-19, provides an understanding of attitudes among rural populations throughout the U.S., including examples that demonstrate the diversity across rural communities. The fourth report describes vaccine coverage by World Health Organization (WHO) region as well as between groups of countries with different economic classifications.

NIS-Child

The children evaluated during the most recent NIS-Child survey were those born during 2019 and 2020. In good news, immunization coverage rates were similar to those found during the previous analysis (2017-2018 births) and included increased coverage with the birth dose of hepatitis B vaccine and at least one dose of hepatitis A vaccine. As such, more than 9 of 10 children had received at least three doses of polio and hepatitis B vaccines and one or more doses of measles, mumps, rubella (MMR) and chickenpox vaccines. And, the percent of children who were completely unvaccinated remained steady at 1%.

However, a few findings are important for our consideration of the relationship between local and societal protection:

1. Not all vaccines enjoyed equal coverage, leading to only about 6 of 10 children having received at least two doses of influenza vaccine and only about 7 of 10 having received the “combined seven-vaccine series” consisting of at least four doses of both DTaP and pneumococcal conjugate vaccines, at least three doses each of polio, Hib and hepatitis B vaccines, and at least one dose of MMR and chickenpox vaccines.
2. State, local and territorial coverage varied, in some cases falling below the 90% coverage thresholds described above.
3. Coverage was also variable when race, ethnicity, poverty status, insurance status, and community type (as defined by U.S. Census data related to metro areas) were considered. In some cases, these disparities were described as “substantial” and were also consistent over time, meaning that overall efforts to remove barriers among certain populations in local communities may not be translating into improvements in coverage.

Kindergarten

The 2022-2023 school year evaluation of vaccine coverage among kindergarteners included children who became eligible to complete school-mandated vaccines during the pandemic. Previous surveys of pre- and post-pandemic vaccine coverage demonstrated about a 2% decline (from 95% to 93%), and the cohort in this year’s survey remained at 93%. However, more alarming were findings related to vaccine exemption rates, which increased in 40 states and the District of Columbia (DC), including 10 states where exemption rates topped 5% for at least one vaccine. According to the discussion section of the report, “The overall percentage of children with an exemption increased from 2.6% during the 2021–22 school year to 3.0% during the 2022–23 school year, the highest exemption rate ever reported in the United States.”

Likewise, coverage rates varied widely across states. For example, 12 states and DC had lower than 90% coverage for vaccines, such as MMR (2 doses), polio (4 doses) and chickenpox (2 doses), and 14 states and DC had less than 90% coverage with DTaP (5 doses). Given the contagiousness of diseases like measles, pertussis and chickenpox, the number of susceptible students in classrooms is concerning.

Rural vaccine confidence

The “CDC’s State of Vaccine Confidence Insights Report,” published in September 2023, evaluated a series of data sources collected between 2017 and 2023 to understand vaccine confidence and uptake among rural populations throughout the U.S. The findings focused on three themes:

1. Vaccine-related concerns regarding safety, effectiveness and necessity
2. Vaccine access and confidence compared with other sub-populations (e.g., urban and suburban populations)
3. The effects of low levels of governmental trust and the politicization of science on vaccine uptake

For each theme, the report highlighted the findings that contributed to them and presented questions to consider and actions that may be taken to address each concern. The report also contained links for more information and additional resources.

A few interesting highlights from this report:

• About 15% of the U.S. population lives in rural areas.
• COVID-19 vaccination among children between 6 months and 4 years of age is paltry regardless of where one lives. Only about 10% of children in urban areas and 3% of those in rural areas have had at least one dose of COVID-19 vaccine. While most children do not get severely ill, some do and a small percentage of them are hospitalized and die. We can and should be working to better protect this vulnerable age group against COVID-19.
• HPV vaccine uptake is 15% lower in rural areas compared with urban areas, and meningococcal vaccine disparities are even worse with a 20% spread between rural and urban teens.
• Barriers that do not relate to vaccine acceptance may be playing an important role. For example, the report cites food insecurity and decreased consumer purchasing power as interfering with individual prioritization of vaccination in rural areas.

Global vaccine coverage

This report evaluated vaccine coverage up to 2022, focusing in particular on progress toward decreasing the number of children who had yet to receive a single dose of diphtheria-tetanus-pertussis-containing (DTP-containing) vaccine (called “zero-dose children”) and increasing the number of those who had received at least three doses of DTP-containing vaccine. Neither of these measurements have returned to pre-pandemic (2019) levels, but both increased from where they were in 2021:

• At least one dose of DTP-containing vaccine: 90% in 2019; 86% in 2021 and 89% in 2022
• At least three doses of DTP-containing vaccine: 86% in 2019; 81% in 2021 and 84% in 2022

The authors made the point that while rates of vaccine coverage are rebounding, “progress was unevenly distributed, especially in low-income countries” (p. 555). For example, only 15 of 73 countries that had a 5% or greater decline in three-dose DTP-containing vaccine coverage have returned to pre-pandemic coverage levels. Coverage is also approaching, but not yet at, pre-pandemic levels for BCG, hepatitis B (3 doses), polio (3 doses) and rubella. Likewise, 115 of 194 WHO member states have yet to return to pre-pandemic coverage levels against measles. Indeed, according to a recent report focused on immunization recovery, it’s estimated that about 128,000 people died from measles in 2021; many of these were unvaccinated or partially vaccinated children younger than 5 years of age.

Because international travel is common and because our society is only as strong as our weakest local communities, it is important to understand that the risk for these diseases to enter the U.S. remains real.

In sum

Vaccinations are local, but infectious diseases are not. By focusing on understanding our own communities and figuring out ways to improve local vaccination rates, we can contribute to not only keeping our neighbors healthy but also ensuring that our community does its part when it comes to protecting our collective society.