COVID-19 models suggest universal vaccination may avert over 100,000 hospitalizations

US Scenario Modeling Hub, a collaborative modeling effort of 17 academic research institutions, reports a universal COVID-19 vaccination recommendation could avert thousands more US hospitalizations and deaths than a high-risk-only strategy.

COVID-19 remains a substantial current public health concern in the US, with higher in-hospital mortality than seasonal influenza during fall-winter 2023–2024.

The Advisory Committee on Immunization Practices (ACIP) sets vaccine use guidance and has traditionally been made up of medical and public health experts within the U.S. Centers for Disease Control and Prevention (CDC). The committee is tasked with framing evidence-based recommendations for the use of vaccines that are effective in controlling diseases.

Recently, the committee has undergone a complete turnover of members, removing seasoned experts in favor of political appointments that include a psychiatrist and several individuals that claim vaccines cause disease. Gone are family physicians and pediatric infectious disease specialists, epidemiologists, geriatric medicine specialists, obstetricians and anyone with experience as a public health implementer.

Scenario modeling offers a way to compare potential future outcomes of ACIP decisions and inform policy for public health groups that will no longer rely on ACIP recommendations.

In the study, “Scenario Projections of COVID-19 Burden in the US, 2024-2025,” published in JAMA Network Open, researchers used a decision-analytical model to project national hospitalizations and deaths from April 2024 to April 2025 and to assess the potential benefit of annual vaccine recommendations.

Nine independent teams produced projections under six scenarios that combined two immune escape rates, 20% and 50% per year. An immune escape rate is the annual reduction in protection against infection that occurs as new SARS-CoV-2 variants evolve. Projections covered the United States population of 332 million with an estimated 58 million aged 65 years.

Three vaccine recommendation strategies were tested. No recommendation, recommendation for high-risk groups only, or recommendation for all eligible individuals. Annually reformulated vaccines were assumed to match variants circulating on June 15, 2024, to be available on September 1, 2024, and to be 75% effective against hospitalization at the time of release.

Teams calibrated their models to weekly hospitalizations and deaths reported by the National Healthcare Safety Network and the National Center for Health Statistics.

In the worst case scenario, defined by high immune escape with no vaccine recommendation, projections reached 931,000 hospitalizations with a 95% projection interval of 0.5 to 1.3 million and 62,000 deaths with a 95% projection interval of 18,000 to 115,000.

In the best case defined by low immune escape with a universal recommendation, the ensemble projected 550,000 hospitalizations with a 95% projection interval of 296,000 to 832,000 and 42,000 deaths with a 95% projection interval of 13,000 to 72,000.

Severe outcomes clustered in older populations. Across scenarios, adults aged 65 years and older accounted for 51% to 62% of hospitalizations and 84% to 87% of deaths.

Vaccination of high-risk groups was only projected to avert 11% of hospitalizations under low immune escape and 8% under high escape, along with 13% and 10% of deaths. A universal recommendation increased the effect with 15% fewer hospitalizations under low immune escape and 11% fewer under high, with 16% and 13% fewer deaths.

Under high immune escape, a high-risk-only strategy averted 76,000 hospitalizations with a 95% CI of 34,000 to 118,000 and 7,000 deaths with a 95% CI of 3,000 to 11,000. Expanding to a universal recommendation prevented 104,000 hospitalizations with a 95% CI of 55,000 to 153,000 and 9,000 deaths with a 95% CI of 4,000 to 14,000.

Additional indirect benefits accrued to older adults under a universal strategy. Compared with high-risk-only vaccination, universal recommendations prevented about 11,000 more hospitalizations and 1,000 more deaths in those aged 65 years and older.

Observed national patterns diverged in timing from projections. A marked summer 2024 wave was followed by a smaller peak in January 2025, while projections anticipated the heaviest burden from late December 2024 to mid January 2025. Ensemble coverage for weekly deaths remained strong, with 95% intervals closely matching observed values.

Authors conclude that vaccines remain a critical tool to limit COVID-19 burden in 2024–2025, with universal recommendations offering added direct and indirect protection and the potential to save thousands more lives, including among older adults.