Effectiveness and Durability of the BNT162b2 KP.2 Vaccine Against COVID-19 Hospitalization and Emergency Department or Urgent Care Encounters in US Adults - Report - MDSpire
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Effectiveness and Durability of the BNT162b2 KP.2 Vaccine Against COVID-19 Hospitalization and Emergency Department or Urgent Care Encounters in US Adults
Efficacy and Durability of BNT162b2 KP.2 Vaccine Against COVID-19 Hospitalizations
Overview
The BNT162b2 KP.2 vaccine demonstrated 49% effectiveness against COVID-19 hospital admissions and 45% against emergency department/urgent care visits within 3 months of vaccination. Protection persisted beyond 90 days with some waning, and effectiveness remained consistent regardless of prior COVID-19 vaccination and in older adults.
Background
In response to the predominant SARS-CoV-2 KP.2 sublineage, the FDA authorized the updated BNT162b2 KP.2 vaccine for individuals aged 6 months and older in 2024. Understanding vaccine effectiveness (VE) and durability is critical to inform vaccination policies. This study evaluated VE against COVID-19 hospitalizations and emergency care visits among adults in a large integrated health system during the 2024–2025 respiratory season.
Data Highlights
Outcome
VE <3 months (95% CI)
VE ≥3 months (95% CI)
Hospital Admission
49% (30–63)
35% (8–54)
ED/Urgent Care Visits
45% (35–54)
26% (12–38)
Key Findings
BNT162b2 KP.2 vaccine effectiveness against COVID-19 hospital admissions was 49% within 3 months post-vaccination, decreasing to 35% after 3 months.
Effectiveness against emergency department or urgent care visits was 45% within 3 months, waning to 26% after 3 months.
VE remained high regardless of prior COVID-19 vaccination history.
Older adults (≥65 years) showed similar VE and waning patterns as younger adults.
Protection persisted beyond 90 days, indicating durability despite some decline.
COVID-19 hospitalizations peaked in December 2024 and January 2025, underscoring ongoing public health burden.
Clinical Implications
The BNT162b2 KP.2 vaccine provides meaningful protection against severe COVID-19 outcomes and emergency care visits, supporting its use in adult populations including older adults. Given the observed waning beyond 3 months, timely booster doses may be considered to maintain protection. Efforts to increase vaccine uptake, especially among those receiving influenza vaccines, could optimize respiratory season preparedness.
Conclusion
The BNT162b2 KP.2 vaccine offers durable protection against COVID-19 hospitalizations and emergency care visits with some waning over time, reinforcing its role in current vaccination strategies for adults.
