Pfizer’s Scottish RSV Maternal Vaccine Study: What Investors Should Watch

Pfizer Inc (PFE) announced an update on their ongoing clinical study.

Study Overview

Pfizer is sponsoring an observational study titled “Evaluating the Benefits Of RSV MaternaL vAccination Using a Scottish National Dataset.” The project aims to measure how well maternal vaccination with ABRYSVO protects infants in Scotland from serious illness caused by respiratory syncytial virus (RSV), especially hospital stays linked to lung infections. The study is important because it uses real-world health records to track outcomes in everyday clinical practice, which can support policy decisions and long-term uptake of maternal RSV vaccines.

Intervention/Treatment

The study focuses on ABRYSVO, a biological medicine (vaccine) given to pregnant women to help protect their babies from RSV after birth. Infants born to mothers who received ABRYSVO at least 14 days before delivery form the “exposed” group. Infants whose mothers did not receive ABRYSVO during pregnancy form the “unexposed” comparison group. No new treatment is given as part of the study; it only analyzes outcomes from routine care.

Study Design

This is an observational, retrospective cohort study. Instead of assigning treatments, researchers will look back at existing national health and demographic records in Scotland. They will compare RSV-related hospitalizations and other outcomes between infants whose mothers received ABRYSVO and those whose mothers did not. There is no randomization, no blinding, and no direct patient contact, which keeps costs lower and reflects real-world use. The main purpose is to assess real-world effectiveness and safety signals in a broad population.

Study Timeline

The study is listed as “not yet recruiting,” but because it uses existing datasets there will be no active enrollment. The protocol was first submitted on November 14, 2025, marking the formal start of regulatory review and setup. The latest update to the record was posted on January 5, 2026, signaling that the design and plans have been recently reviewed and confirmed. Primary completion and final completion dates are not yet specified, but investors should expect results only after enough infants reach 6–12 months of age for meaningful outcome comparisons.

Market Implications

For Pfizer (PFE), this study supports the commercial story for ABRYSVO in maternal immunization. Strong real-world data showing fewer RSV-related hospitalizations would help health authorities and payers justify broad adoption, which could lift long-term revenue and support valuation for Pfizer’s vaccine franchise. It may also strengthen Pfizer’s position versus competitors in the RSV space that are targeting older adults and infants through different strategies. Conversely, weaker-than-expected protection or safety concerns could slow uptake or pressure pricing. For now, the latest update mainly signals ongoing investment in evidence-building rather than a near-term catalyst, but positive future readouts could shift investor sentiment toward more confidence in ABRYSVO’s peak-sales potential and Pfizer’s broader post-pandemic vaccine pipeline. The study remains ongoing and updated, with further details available on the ClinicalTrials portal.

To learn more about PFE’s potential, visit the Pfizer Inc drug pipeline page.