Moderna Targets Mid-Age Adults With New Variant COVID-19 Booster Study

Moderna (MRNA) announced an update on their ongoing clinical study.

Moderna’s latest Phase 4 study, titled “A Phase 4, Randomized, Observer-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of mRNA-1283 And mRNA-1273 Variant-Containing Formulation in Adults 50 to 64 Years of Age Without Underlying Conditions That Put Them at High Risk for Severe Outcomes From COVID-19,” aims to test how well updated COVID-19 vaccines protect generally healthy adults in their 50s and early 60s. The study focuses on both effectiveness and safety, and its results could guide the next stage of booster strategy and revenue visibility for Moderna in a key age group.

The interventions are two Moderna COVID-19 vaccines, mRNA-1273 and mRNA-1283, both in updated “variant” formulations designed to better match circulating strains of the virus. Each is given as a single muscle injection and compared with a placebo (a saltwater injection). The goal is to show that these newer shots can reduce infections and severe outcomes in people without high-risk medical conditions.

The trial uses a randomized, parallel-group design, meaning participants are randomly assigned to one of three groups: mRNA-1273, mRNA-1283, or placebo, and they stay in that group for the study. It is “observer-blind,” with masking for participants, investigators, and those who assess outcomes, so they do not know who received which shot. The primary purpose is prevention, testing whether one-time vaccination lowers the risk of COVID-19 compared with placebo.

The study was first submitted on November 25, 2025, marking the formal start of regulatory tracking and site activation. The most recent update was filed on December 9, 2025, showing that the trial design and status are current and that the study remains active. The status is “recruiting,” which means enrollment is still underway and no primary completion or final completion dates have yet been reached; key readouts will follow once enough participants have been enrolled and monitored.

For investors, this update reinforces Moderna’s push to defend and extend its COVID-19 vaccine franchise as the market shifts from emergency demand to seasonal, booster-like use. Positive data in a lower-risk, mid-age adult segment would support a broader recurring revenue base and strengthen the case for updated mRNA boosters, which may help sentiment around MRNA shares, especially if uptake trends stabilize. However, competition from Pfizer-BioNTech and other vaccine makers remains intense, and the market is more mature, so investors should view upside as incremental rather than transformational. The trial’s progress signals continued investment in next-gen COVID products, and the study is currently ongoing with more details available on the ClinicalTrials.gov portal.

To learn more about MRNA’s potential, visit the Moderna drug pipeline page.