Key Clinical Summary: 

• A phase 3 study of 672 participants evaluated the safety and immunogenicity of the Pfizer-BioNTech LP.8.1 variant-adapted COVID-19 vaccine in adults aged 65 years or older and younger individuals at increased risk for severe disease.
• Most reported local and systemic reactions were mild or moderate, with no immediate adverse events, adverse events leading to withdrawal, or deaths reported through 1 month after vaccination.
• The vaccine met predefined immunogenicity criteria in both age groups, demonstrating increased neutralizing antibody levels 1 month after vaccination.

A single dose of the Pfizer-BioNTech LP.8.1 variant-adapted COVID-19 vaccine demonstrated a favorable short-term safety profile and robust immune responses among older adults and individuals at increased risk for severe COVID-19, according to phase 3 research presented at IDWeek 2026.

The findings may be particularly relevant to long-term care clinicians responsible for protecting older adults and medically vulnerable residents from COVID-19 complications.

Phase 3 Study Evaluates High-Risk Populations

Researchers conducted an open-label phase 3 study evaluating a single 30-µg dose of BNT162b2 adapted to the LP.8.1 SARS-CoV-2 variant.

The study enrolled 672 participants, including 337 individuals aged 12 to 64 years with underlying risk factors and 335 adults aged 65 years or older.

Participants were excluded if they had experienced COVID-19 illness or received a COVID-19 vaccine within the preceding 150 days. Previous vaccination was not required.

Safety assessments included monitoring for adverse events, while immunogenicity was evaluated through neutralizing antibody testing before vaccination and 1 month afterward.

Vaccine Demonstrates Favorable Short-Term Safety and Immunogenicity

Of 672 enrolled participants, 671 received the vaccine. Most local and systemic reactions were mild or moderate, with injection site pain and fatigue reported most frequently.

Overall, 43 participants (6.4%) reported adverse events through 1 month. No immediate adverse events, adverse events leading to withdrawal, adverse events of special interest, or deaths were reported during this period.

Neutralizing antibody levels increased in both age groups, with geometric mean fold rises of 15.1 among participants aged 12 to 64 years and 7.7 among adults aged 65 years or older.

Both groups met predefined immunogenicity criteria.

Implications for Long-Term Care

The findings provide encouraging immunogenicity and short-term safety data for an updated COVID-19 vaccine in populations at increased risk for severe illness.

However, the study did not directly evaluate protection against infection, hospitalization, or death, and longer-term safety follow-up is ongoing. The findings also were not specific to nursing home residents.

For long-term care clinicians, the results contribute to the evidence base for vaccination discussions involving older adults and medically vulnerable patients.

Reference 

Cardona JF, DeHaan EN, Peterson J, et al. A phase 3 study to investigate the safety, tolerability, and immunogenicity of BNT162b2 RNA-based variant-adapted vaccine candidate (LP.8.1) against SARS-CoV-2 in participants 12 through 64 years of age considered at higher risk of severe COVID-19 and participants ≥ 65 years of age. Poster presented at: IDWeek 2026. October 21-24, 2026. Washington, DC. P-2112. Accessed October 30, 2026. https://idweek2026.eventscribe.net/fsPopup.asp?PosterID=838113&mode=posterInfo