Mahmud Sheku, MPH, MS, PhD Student. Emory University Rollins School of Public Health, Atlanta, Geogia, USA. Contributions: Connor Van Meter, MSPH; Robert A. Bednarczyk, PhD; Kathrine Seib, MSPH; Emilia Grill, MPH; and Benjamin A. Lopman, PhD.
Recent declines in childhood vaccination coverage in the United States have raised concern among vaccine scientists. Kindergarten vaccination rates have decreased across multiple states1 (CDC 2023), and exemption rates for one or more childhood vaccines increased from 3.3% to 3.6% across 40 states2. At the same time, measles cases in 2024-2025 have surged, reaching over 2,000 reported cases nationally3, the highest number recorded in the U.S. since 1991. Reported pertussis cases have also increased substantially compared to prior years4.
These trends highlight how quickly vaccine preventable diseases can re-emerge when population immunity declines. While measles has drawn public attention, declines in coverage may also affect other vaccine-preventable diseases, including rotavirus, pertussis, and invasive pneumococcal disease (IPD), that receive comparatively less sustained media focus despite imposing a substantial health and economic burden. Because disease transmission is nonlinear, even modest sustained reductions in coverage can allow susceptible individuals to accumulate across birth cohorts, increasing outbreak risk and amplifying downstream population-level health and economic consequences.
At the same time, childhood immunization policy in the U.S. is in flux. In early 2026, following a presidential memorandum directing a review of the U.S. vaccine practices relative to peer nations, the Department of Health and Human Services and the Centers for Disease Control and Prevention (CDC) updated the childhood immunization schedule5. Under this revised framework, the rotavirus vaccine and five other vaccines that were previously recommended universally for all children are now only recommended for high-risk groups or through shared clinical decision-making. These changes represent a departure from the traditional Advisory Committee on Immunization Practices (ACIP) consensus process. As a result, differences have emerged between federal recommendations and immunization schedules maintained by professional organizations such as the American Academy of Pediatrics, potentially adding complexity to clinical decision-making. Public health experts have noted the on potential impact of such changes on vaccine uptake, confidence, and disease outcomes.
In this evolving immunization landscape shaped by vaccine hesitancy, misinformation, and ongoing policy discussions, policymakers and public health leaders need tools that translate changes in vaccine coverage into projected health and economic consequences. To address this need, our team at Emory University’s Rollins School of Public Health developed VaxImpact6, a publicly available, interactive, state-specific decision-support platform that projects the additional burden associated with declining infant vaccination.
What is VaxImpact?
VaxImpact is a decision-support tool that uses calibrated, state-level equilibrium transmission models to estimate how reductions in infant vaccination coverage could affect disease burden across U.S. states. It provides state-level projections, accounting for differences in baseline state-level vaccination coverage, state-specific population size, birth cohort structure, and transmission dynamics.
This initial release modeled three routine childhood vaccine preventable diseases, including rotavirus (diarrheal disease), pertussis (whooping cough), and invasive pneumococcal disease (IPD). These diseases have predictable relationship between vaccination coverage and their corresponding disease burden.
Rotavirus was modeled using a Susceptible-Infection-Recovered (SIR) framework. Pertussis and IPD are modeled using a Susceptible-Infection-Recovered-Susceptible (SIRS) framework with waning immunity. Models incorporated state-specific population size, birth rates and vaccination coverage. Coverage declines of 0-20 percentage points were applied to infant cohorts and translated into effective age-band coverage. We compared a one-year shock scenario with a five-year sustained decline scenario in which reduced coverage accumulates across successive birth cohorts. Models were calibrated to reproduce national surveillance-based disease burden and vaccination impact patterns. Outcomes include additional annual cases, hospitalizations, deaths, missed workdays, and total economic costs (direct medical costs and productivity losses).
How does the tool work?
VaxImpact allows users to simulate vaccine coverage declines and explore projected impact in real time. Users can select one of the three modeled diseases, specify a coverage decline (0-20 percentage points), choose between a one-year shock or a sustained five-year decline scenario, and toggle between total burden and additional burden to see the impact attributable to declining coverage in each state. For each state, the platform dynamically updates projections of additional annual cases, hospitalizations, deaths, lost workdays, and total costs. Users can hover over individual states to view state-specific characteristics and projected outcomes.
What do we project?
One-year 0-20% decline
Nationally, a one-year 20% decline in infant vaccination coverage is projected to result in 230,358 additional rotavirus cases (3,294 hospitalizations; 2 deaths), 13,559 additional pertussis cases (644 hospitalizations; 6 deaths), and 1,426 additional IPD cases (1,183 hospitalizations; 44 deaths), with associated annual total costs of $259 million, $44 million, and $25 million, respectively.
Five-year 0-20% decline
Following a five-year decline of 20%, impacts increase substantially due to the accumulation of susceptible children, resulting in 809,819 additional rotavirus cases (11,580 hospitalizations; 6 deaths), 56,502 additional pertussis cases (2,768 hospitalizations; 27 deaths), and 4,631 additional IPD cases (3,844 hospitalizations; 142 deaths), with projected annual disease-specific total costs exceeding $911 million, $183 million, and $81 million, respectively.
State-level variation
Projected impacts vary substantially across states. This variation reflects differences in baseline vaccination coverage, population size, birth cohort structure, and state-specific transmission dynamics.
For instance, under a sustained five-year 20% decline in vaccine coverage for each of the modeled disease:
Rotavirus: National rotavirus burden in under five children is projected to increase by 154% by 2031. In states with higher population and low to moderate baseline coverage, like Texas, the scenario could result in 6,542 additional cases per 100,000 children (a 354% increase in disease burden) compared to 3,671 additional cases per 100,000 children (a 97% increase) in Georgia by 2031.
Pertussis: National pertussis burden in children under 14 years is projected to increase by 65% by 2031. In Texas, the scenario could result in 108 additional cases per 100,000 children (a 54-fold increase) compared to 71 additional cases per 100,000 children (a 72% increase) in Florida by 2031.
Invasive Pneumococcal Disease: National IPD burden in under five children is projected to increase by 98% by 2031. In California, the scenario could result in 19 additional cases per 100,000 children (a 112% increase in disease burden) compared to 16 additional cases per 100,000 children (a 76% increase) in Florida by 2031.
These findings demonstrate how sustained reductions in coverage can lead to disproportionate increases in disease burden and economic losses borne by families, healthcare systems, insurers, employers, and state and federal public health programs.
Why does this matter now?
The resurgence of measles and the increase in pertussis cases have demonstrated how quickly vaccine-preventable diseases can return when population immunity declines. While measles often serves as the visible signal of coverage erosion, other diseases may increase more quietly but still pose substantial burden with real consequences for individuals, children, families, public health, and the U.S. health care system.
As vaccination policy discussions intensify at both federal and state levels, stakeholders require evidence-based projections to inform immunization program planning, legislative discussions, public communication strategies, and resource allocation. By translating changes in vaccine uptake into projected additional cases, hospitalizations, deaths, and economic costs, the VaxImpact helps quantify the potential consequences of declining coverage to inform ongoing immunization policy debates and outbreak prevention efforts.
Looking ahead
Routine childhood immunization programs have dramatically reduced morbidity and mortality from vaccine-preventable diseases in the United States over the past six decades. These gains were achieved through sustained high vaccination coverage, strong public health infrastructure, and consistent immunization policy. However, this progress can erode quickly if coverage declines. Rebuilding population immunity after sustained reductions may take years, particularly as susceptible individuals accumulate across birth cohorts. Maintaining these gains, therefore, requires science-driven immunization policies aimed at sustaining higher coverage levels. In an evolving immunization landscape, a publicly available scenario-based tool like VaxImpact can support proactive planning and evidence-based policymaking.
We invite vaccine researchers, immunization program leaders, and policymakers to explore the platform and consider how state-specific projections can inform local decision-making.
Future development of VaxImpact will expand to additional vaccine-preventable diseases, age groups, and other granularity, further enhancing the tool’s utility for immunization program planning and policy evaluation.
Reference
- CDC. Vaccination Coverage and Exemptions among Kindergartners. SchoolVaxView. July 31, 2025. Accessed March 1, 2026. https://www.cdc.gov/schoolvaxview/data/index.html
- Seither, R. Coverage with Selected Vaccines and Exemption from School Vaccine Requirements Among Children in Kindergarten — United States, 2022–23 School Year.
- CDC. Measles Cases and Outbreaks. Measles (Rubeola). February 27, 2026. Accessed March 1, 2026. https://www.cdc.gov/measles/data-research/index.html
- CDC. Pertussis Surveillance and Trends. Whooping Cough (Pertussis). January 5, 2026. Accessed March 1, 2026. https://www.cdc.gov/pertussis/php/surveillance/index.html
- Affairs (ASPA) AS for P. [node.field_full_title]. January 5, 2026. Accessed March 1, 2026. https://www.hhs.gov/press-room/cdc-acts-presidential-memorandum-update-childhood-immunization-schedule.html
- VaxImpactMap: Costs of Declining Childhood Vaccination. VaxImpactMap. Accessed March 1, 2026. https://vaximpactmap.org/
