Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design - Summary - MDSpire

Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design

  • By

  • Ryan E. Wiegand

  • Sean Chickery

  • Duck-Hye Yang

  • Sarah W. Ball

  • Malini B. DeSilva

  • Kristin Dascomb

  • Stephanie A. Irving

  • Karthik Natarajan

  • Nicola P. Klein

  • Shaun J. Grannis

  • Toan C. Ong

  • Elizabeth A. K. Rowley

  • Adam Yates

  • Yan Zhuang

  • Sarah Wilson

  • Charlene E. McEvoy

  • Inih J. Essien

  • Omobosola O. Akinsete

  • Allison L. Naleway

  • Padma Koppolu

  • Ousseny Zerbo

  • John R. Hansen

  • Karen B. Jacobson

  • Lawrence Block

  • Brian E. Dixon

  • Thomas Duszynski

  • Colin Rogerson

  • Michelle A. Barron

  • Catia Chavez

  • Josephine Mak

  • Allison Avrich Ciesla

  • Monica Godfrey

  • Amber Kautz

  • Morgan Najdowski

  • Ruth Link-Gelles

  • Jennifer DeCuir

  • Amanda B. Payne

  • June 23, 2026

  • 0 min

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Objective:

To estimate vaccine effectiveness (VE) against COVID-19–associated emergency department and urgent care encounters and hospitalizations among immunocompetent adults aged 18 years or older from September 3, 2025, to December 31, 2025.

Approach:
    Key Findings:
    • A total of 85,725 ED/UC encounters were analyzed from September 3, 2025, to December 31, 2025, with 3941 case patients (5%) testing positive for SARS-CoV-2.
    • Overall, 9659 patients (11%) had received a 2025-2026 COVID-19 vaccine.
    Interpretation:

    Vaccine effectiveness was calculated as (1 − aOR) × 100%, with analyses stratified by age groups during the study period.

    Limitations:
    • Limited statistical power precluded further analyses.
    • Exclusions were made for patients with certain co-infections and vaccination behaviors.
    Conclusion:

    The study provides preliminary estimates of COVID-19 vaccine effectiveness for the 2025-2026 period among adults.

Original Source(s)

Interim Estimated Effectiveness of 2025-2026 COVID-19 Vaccines in Adults Using a Test-Negative Design

  • by Ryan E. Wiegand, Sean Chickery, Duck-Hye Yang, Sarah W. Ball, Malini B. DeSilva, Kristin Dascomb, Stephanie A. Irving, Karthik Natarajan, Nicola P. Klein, Shaun J. Grannis, Toan C. Ong, Elizabeth A. K. Rowley, Adam Yates, Yan Zhuang, Sarah Wilson, Charlene E. McEvoy, Inih J. Essien, Omobosola O. Akinsete, Allison L. Naleway, Padma Koppolu, Ousseny Zerbo, John R. Hansen, Karen B. Jacobson, Lawrence Block, Brian E. Dixon, Thomas Duszynski, Colin Rogerson, Michelle A. Barron, Catia Chavez, Josephine Mak, Allison Avrich Ciesla, Monica Godfrey, Amber Kautz, Morgan Najdowski, Ruth Link-Gelles, Jennifer DeCuir, Amanda B. Payne

  • June 23, 2026

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