Projected Public Health Impact of Synchronized COVID-19 and Influenza Vaccination With a Combination Vaccine in US Older Adults
Author(s)
Kelly Fust, MS1, Michele Kohli, MSc, PhD1, Shannon Cartier, Msc1, Nicolas Van de Velde, MBA, MSc, PhD2, Darshan Mehta, MBA, PhD2.
1Quadrant Health Economics Inc., Cambridge, ON, Canada, 2Moderna, Cambridge, MA, USA.
1Quadrant Health Economics Inc., Cambridge, ON, Canada, 2Moderna, Cambridge, MA, USA.
OBJECTIVES: COVID-19 and influenza remain major contributors to disease burden in U.S. adults aged ≥65 years. Asynchronous vaccine campaign may reduce overall vaccine uptake. Investigational combination vaccines offer a convenient option that could increase coverage and improve health outcomes. This study estimated the potential public health impact of synchronizing COVID-19 and influenza vaccination during the 2023/24 respiratory season in older adults (65+).
METHODS: A static model, calibrated to U.S. CDC hospitalization data (September 2023-August 2024), projected infections, hospitalizations, and deaths due to COVID-19 and influenza. The base case reflected observed, asynchronous vaccine coverage rates (VCRs) and used CDC-derived influenza vaccine effectiveness (VE) and real-world VE data for the mRNA-1273 COVID-19 vaccine. Four scenarios were modeled: Scenario 1: Synchronized vaccine administration in September using observed VCRs. Scenario 2: Scenario 1 plus improved VE reflecting next-generation COVID-19 vaccines (e.g., mRNA-1283). Scenario 3: Scenarios 2 plus an absolute 10% (3a) or 20% (3b) increase in COVID-19 VCR. Scenario 4: Scenarios 3a and 3b with an approximate 3% increase in influenza VCR. The increase in VCR was based on consumer preference for combination vaccine.
RESULTS: In the base case, the model projected 525,079 COVID-19 and 136,523 influenza-related hospitalizations. Scenario 1 prevented an additional 7,137 COVID-19 hospitalizations through simple synchronization of vaccine timing. Scenario 2 projected 16,454 fewer COVID-19 hospitalizations. Scenarios 3a and 3b prevented 50,403 and 84,352 COVID-19 hospitalizations with a 10% or 20% increase in COVID VCR, respectively. Influenza hospitalizations remained stable across Scenarios 1-3, assuming unchanged VE and VCR. Scenarios 4a and 4b projected the largest reductions, preventing 54,129 and 88,078 COVID hospitalizations, respectively, and 1,017 influenza hospitalizations each.
CONCLUSIONS: A synchronized COVID-19 and influenza vaccination campaign could significantly reduce COVID-19 hospitalizations. Combination vaccines incorporating next generation vaccines may further amplify this benefit via improved efficacy and driving uptake.
METHODS: A static model, calibrated to U.S. CDC hospitalization data (September 2023-August 2024), projected infections, hospitalizations, and deaths due to COVID-19 and influenza. The base case reflected observed, asynchronous vaccine coverage rates (VCRs) and used CDC-derived influenza vaccine effectiveness (VE) and real-world VE data for the mRNA-1273 COVID-19 vaccine. Four scenarios were modeled: Scenario 1: Synchronized vaccine administration in September using observed VCRs. Scenario 2: Scenario 1 plus improved VE reflecting next-generation COVID-19 vaccines (e.g., mRNA-1283). Scenario 3: Scenarios 2 plus an absolute 10% (3a) or 20% (3b) increase in COVID-19 VCR. Scenario 4: Scenarios 3a and 3b with an approximate 3% increase in influenza VCR. The increase in VCR was based on consumer preference for combination vaccine.
RESULTS: In the base case, the model projected 525,079 COVID-19 and 136,523 influenza-related hospitalizations. Scenario 1 prevented an additional 7,137 COVID-19 hospitalizations through simple synchronization of vaccine timing. Scenario 2 projected 16,454 fewer COVID-19 hospitalizations. Scenarios 3a and 3b prevented 50,403 and 84,352 COVID-19 hospitalizations with a 10% or 20% increase in COVID VCR, respectively. Influenza hospitalizations remained stable across Scenarios 1-3, assuming unchanged VE and VCR. Scenarios 4a and 4b projected the largest reductions, preventing 54,129 and 88,078 COVID hospitalizations, respectively, and 1,017 influenza hospitalizations each.
CONCLUSIONS: A synchronized COVID-19 and influenza vaccination campaign could significantly reduce COVID-19 hospitalizations. Combination vaccines incorporating next generation vaccines may further amplify this benefit via improved efficacy and driving uptake.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
EE620
Topic
Clinical Outcomes, Economic Evaluation, Epidemiology & Public Health
Disease
Vaccines