Shots Missed: The Troubling Decline in Childhood Vaccines

As measles cases surge in Texas, claiming several lives over the past year, recent studies from the Centers for Disease Control and Prevention (CDC) reveal a troubling nationwide decline in childhood vaccination rates. These first measles deaths in the U.S. since 2015 underscore the real-world consequences of vaccination gaps. The Advisory Committee on Immunization Practices recommends immunization against fifteen potentially serious illnesses for children by age 24 months, making these declining rates an urgent public health concern.

Holly Hill and colleagues analyzed vaccination data for children at age 24 months using the National Immunization Survey. Their findings show that vaccination coverage was significantly lower among children born in 2020 and 2021 compared to those born in 2018 and 2019. This decline coincides directly with the COVID-19 pandemic, which severely disrupted routine health care visits and created unprecedented barriers to preventive care.

The researchers documented drops of 1.3-7.8% across vaccines, with flu vaccination seeing the steepest decline. While some vaccines still maintained relatively high coverage—polio vaccine (91.9%), measles, mumps, and rubella vaccine (90.3%), and hepatitis B vaccine (91.1%)—these rates fall below the crucial 95% threshold that doctors consider necessary to prevent disease outbreaks in communities.

The current Texas outbreak […] exemplifies how quickly preventable diseases can spread when vaccination rates drop.

The study revealed significant social and economic disparities in vaccination coverage that intensified during the pandemic. Children from minority communities, those below the federal poverty level, and those in rural areas had substantially lower vaccination rates than their counterparts. The gap was particularly stark with flu vaccines, where researchers found a 19.9 percentage point difference between children above and below the poverty line. As clinics reduced hours, postponed well-child visits, and faced staffing shortages during COVID-19, these access barriers disproportionately affected already vulnerable populations.

While the Hill study examines pandemic-related barriers to vaccination in younger children, another dimension of the vaccination challenge emerges when children reach school age. A second major study led by Ranee Seither and colleagues explored vaccination coverage and exemption rates among kindergartners across 49 states during the 2018-2019 school year—just before the pandemic began. The researchers assessed coverage for required vaccines and how many children were exempt from these requirements.

This kindergarten study found that nationwide, vaccination coverage remained at approximately 95% for key childhood vaccines, including those protecting against diphtheria, tetanus, and whooping cough (DTaP); measles, mumps, and rubella (MMR); and chickenpox (varicella). However, the researchers identified a concerning rise in exemption rates. Specifically, 2.5% of kindergartners had exemptions from one or more vaccines—an increase from 2.3% in the previous school year. While medical exemptions accounted for just 0.3%, non-medical exemptions—based on personal, philosophical, or religious beliefs—made up 2.2%. Unlike the access issues identified in Hill’s study, these exemptions often reflect deliberate choices to opt out of vaccination requirements.

The resurgence of measles—a disease declared eliminated in the U.S. in 2000—serves as a tragic reminder of what’s at stake.

Perhaps most concerning is what the kindergarten study revealed about states with high exemption rates. In 25 states, more kindergartners simply hadn’t completed their vaccinations (without formal exemptions) than those with official exemptions. These children often attended school under “grace periods” or “provisional enrollment” while supposedly completing their vaccination schedules. The researchers noted that nearly all states could reach the critical 95% measles vaccination threshold if these children—who don’t have exemptions—were simply brought up to date according to existing requirements.

Together, these studies paint a comprehensive picture of the vaccination landscape in the United States—from early childhood through school entry—revealing that both access barriers and exemption trends contribute to vaccination gaps.

The consequences of these gaps are now becoming evident. Measles cases nationwide reached alarming levels in 2024, with the U.S. reporting 285 cases—exceeding the total number of cases reported in the previous four years combined. Notably, 89% of these cases occurred in unvaccinated individuals or those with unknown vaccination status. The current Texas outbreak, which has affected 223 people since late January 2025, exemplifies how quickly preventable diseases can spread when vaccination rates drop. Twenty-nine patients have been hospitalized, highlighting the serious nature of what was once considered a largely controlled disease.

The resurgence of measles—a disease declared eliminated in the U.S. in 2000—serves as a tragic reminder of what’s at stake. The CDC urges parents to check with their children’s doctors to ensure they are up to date on all recommended vaccines. For children who have fallen behind, catch-up vaccination schedules are available.