On May 28, 2025, Moderna announced that it has received notice from the U.S. Department of Health and Human Services (HHS) that it has terminated the award for the late-stage development and right to purchase pre-pandemic influenza vaccines. The Company had previously expected to advance the program to late-stage development with the U.S.

The company also announced positive interim data from a Phase 1/2 clinical study (NCT05972174) evaluating the safety and immunogenicity of its investigational pandemic influenza vaccine, mRNA-1018, in approximately 300 healthy adults aged 18 years and older. The interim results focus on a vaccine candidate targeting the H5 avian influenza virus subtype.

The Phase 1/2 study evaluated a two-dose regimen of Moderna’s investigational avian influenza vaccine. mRNA-1018 demonstrated a rapid, potent and durable immune response. At baseline, pre-existing immunity was minimal, with only 2.1% of participants showing hemagglutination inhibition (HAI) antibody titers ≥1:40, an HAI titer considered to correlate with protection. At Day 43, three weeks after the second vaccination, 97.8% of participants achieved titers ≥1:40 with a 44.5-fold increase of titers from baseline.

The investigational vaccine was generally well-tolerated, with no dose-limiting tolerability concerns observed. Most solicited adverse reactions were Grade 1 or 2 and did not increase significantly with number of doses or between first and second doses.

Moderna will explore alternatives for late-stage development and manufacturing of the H5 program consistent with the Company’s strategic commitment to pandemic preparedness.