A 10% vaccine coverage drop could add hundreds of thousands of childhood infections

Emory University modelling shows how falling immunisation rates could drive additional infections, hospitalisations, deaths and costs, with Florida among the states most exposed.

A new mapping tool from Emory University is putting numbers on what falling childhood vaccination coverage could mean for children, families and state health systems. The VaxImpactMap project estimates that even a modest 10% drop in immunisation rates could have measurable consequences across several vaccine-preventable diseases, including respiratory syncytial virus, rotavirus, pertussis, pneumococcal disease and Haemophilus influenzae type b, or Hib. According to Emory, the model is designed to help public health officials see how coverage changes might translate into illness, hospital care, deaths and economic costs.

For respiratory syncytial virus, better known as RSV, the project projects an additional 79,000 cases, 4,800 hospitalisations and 11 deaths each year if coverage were to fall by 10%. Rotavirus, a highly contagious cause of severe diarrhoeal illness in young children, shows an even larger burden in the model: 385,000 more cases, 5,500 hospitalisations and three deaths annually, along with roughly $572 million in healthcare and productivity costs. The Centres for Disease Control and Prevention says both infections can be especially dangerous for infants and young children, which is why vaccination remains a central prevention strategy.

The tool also extends to pertussis, pneumococcal disease and Hib, allowing users to test coverage declines from 0% to 20% and see estimated effects on missed workdays, productivity losses and hospital expenses. Emory says the projections are calibrated to current state-level coverage, birth rates and surveillance data, giving the map a local rather than purely national focus. That matters because the same percentage drop does not produce the same result everywhere; the model shows that consequences vary widely depending on population size, birth rates, baseline uptake and existing disease burden.

Florida stands out in the estimates as a state where policy changes could have especially large effects. Under a 10% fall in rotavirus coverage, the model projects 380 additional hospitalisations in Florida compared with 37 in New Mexico. Emory also points to a proposed rule change in Florida that would end school or daycare entry requirements for varicella, Hib, pneumococcal and hepatitis B vaccines. In the company’s modelling, a 10% decline in varicella vaccination over five years could lead to 25,000 extra cases, 222 hospitalisations, two deaths and more than $50 million in related costs.

The broader lesson, according to the researchers behind the map, is that states with lower existing coverage have less room to absorb further declines. That is because they are already closer to the threshold at which herd immunity weakens, leaving communities more exposed to outbreaks. For policymakers and health departments, the tool is meant to support comparisons with national benchmarks and to highlight the potential consequences of exemption policies or pending legislation before coverage slips further.