Pfizer–BioNTech COVID-19 Vaccine Elicits Robust Responses in High-Risk Adults

A 30-µg dose of the LP.8.1-adapted monovalent mRNA COVID-19 vaccine (Comirnaty; Pfizer­–BioNTech) elicited a robust increase in neutralizing antibodies towards the LP.8.1 sublineage of SARS-CoV-2 following vaccination in adults aged 65 and older and individuals aged 18 through 64 with at least 1 underlying risk condition for severe COVID-19, according to newly released topline data from Pfizer and BioNTech.¹

Pfizer and BioNTech's adapted COVID-19 vaccine was recently approved by the FDA. | Image Credit: © diy13 - stock.adobe.com

The findings support the preclinical data that led to the FDA approval of Pfizer-BioNTech’s LP.8.1-adapted COVID-19 vaccine. Along with that approval, the FDA approved Novavax’s Nuvaxvoid and Moderna’s Spikevax and mNEXSPIKE, all COVID-19 vaccines that are adapted to target the LP.8.1 sublineage of SARS-CoV-2. For now, Pfizer–BioNTech is the only manufacturer that has released topline data—in addition to preclinical results­—supporting the approval.^1,2

Earlier this year, the FDA—following a meeting of the Vaccines and Related Biological Products Advisory Committee—had recommended that COVID-19 vaccines for the 2025-2026 respiratory season be monovalent with a JN.1-lineage base and preferably target the LP.8.1 strain. Throughout 2025, LP.8.1 has been one of the most dominant SARS-CoV-2 strains circulating in the United States.^1,3,4

Trial Finds Robust Immune Responses

In the open-label, phase 3 trial, 100 participants were enrolled—50 adults aged 65 and older and 50 adults aged 18 through 64 with at least 1 risk condition for severe COVID-19. Prior to receiving the updated LP.8.1-targeting vaccine formula, all enrollees had previously received the KP.2-adapted COVID-19 vaccine. This had to be completed at least 6 months prior to enrollment in the trial; the individuals must not have received any other COVID-19 vaccine or had COVID-19 disease since the KP.2 vaccination.¹

For each age group—14 days post-vaccination—LP.8.1-neutralizing antibody titers were observed to exceed prevaccination levels by at least 4-fold, on average, the investigators announced. Importantly, the safety profile of the vaccine was consistent with previous studies and the known safety profile of the immunization, which includes a remote chance of severe allergic reaction or a rare risk of myocarditis.¹

Implications for Pharmacists

With this new data, pharmacists now have additional information at their disposal regarding the specific immunological effects of the vaccine that they can provide to patients. Pfizer–BioNTech note in their news release that the study is not intended to replace post-marketing commitments requested by the FDA. The necessity of these post-marketing trials was first announced in an editorial in the New England Journal of Medicine by FDA Commissioner Martin A. Makary, MD, MPH. Makary wrote that, when approving COVID-19 vaccines for high-risk groups, the FDA would encourage manufacturers to conduct post-marketing randomized controlled trials in healthy adults.^1,5

Currently, COVID-19 is surging throughout the country. For the week ending on August 30, 2025, SARS-CoV-2 test positivity across the United States was 10.8%. Though it was a drop from the prior week, when the test positivity rate was 11.6%, it is the highest weekly test positivity since September 2024. Accordingly, the percent of emergency department visits diagnosed as COVID-19 for the same week was 1.6%, also the highest since September 2024.^1,6

Fortunately, death and hospitalization rates remain reduced since the emergency phase of the pandemic. However, just because COVID-19 has receded to being endemic does not mean pharmacists shouldn’t remain vigilant about counseling patients on the benefits of vaccination. In fact, pharmacists are poised to play a bigger role than ever. With so much news regarding COVID-19 vaccines circulating, misinformation is liable to be spread to patients. Pharmacists are integral in providing trustworthy, fact-based counseling to patients who may seek or have questions about a COVID-19 vaccine.^1,6

REFERENCES

1. Pfizer and BioNTech Announce Topline Data Demonstrating Robust Immune Response With Their LP.8.1-Adapted COVID-19 Vaccine 2025-2026 Formula. Pfizer. News Release. Released September 8, 2025. Accessed September 9, 2025. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-topline-data-demonstrating

2. Halpern L. FDA Approves Updated COVID-19 Vaccines Targeting LP.8.1 For Older Adults, Those At Risk. Pharmacy Times. Published August 27, 2025. Accessed September 9, 2025. https://www.pharmacytimes.com/view/fda-approves-pfizer-biontech-s-updated-covid-19-vaccine-for-older-adults-those-at-risk

3. Halpern L. FDA Recommends 2025-2026 COVID-19 Vaccines Be Monovalent, Target LP.8.1 Strain. Pharmacy Times. Published May 27, 2025. Accessed September 9, 2025. https://www.pharmacytimes.com/view/fda-recommends-2025-2026-covid-19-vaccines-be-monovalent-target-lp-8-1-strain

4. Halpern L. FDA to Restrict Future COVID-19 Vaccine Recommendations to Older Adults, High-Risk Groups. Pharmacy Times. Published May 21, 2025. Accessed September 9, 2025.

5. CDC—National Wastewater Surveillance System (NWSS). Variants in wastewater. Accessed September 9, 2025. https://www.cdc.gov/nwss/rv/COVID19-variants.html

6. CDC—Surveillance and Data Analytics. COVID-19 surveillance data in the United States. Last Updated September 5, 2025. Accessed September 9, 2025. https://www.cdc.gov/covid/php/surveillance/index.html