Moderna has pushed its pandemic preparedness program into a new phase.

 

The pharma powerhouse has announced that the first participants in the US and UK have been dosed in a Phase 3 trial of its investigational mRNA-based H5 influenza vaccine candidate, mRNA-1018.

 

The late-stage study marks a major step forward in the company’s bid to develop a scalable response to future flu pandemics. 

 

Backed in part by the Coalition for Epidemic Preparedness Innovations (CEPI), which in December 2025 committed up to $54.3 million to support development through potential licensure, the program is now moving into large-scale human testing.

 

“H5 influenza, or bird flu, remains a pandemic threat. The start of our Phase 3 trial for an H5 influenza vaccine marks a significant milestone in our ongoing efforts to strengthen global pandemic preparedness," said Stéphane Bancel, Chief Executive Officer of Moderna. 

 

"Our platform technology's efficiency and scalability are critical to supporting global health security and responding to potential future threats."

 

CEPI says the trial could reshape how the world responds to emerging infectious diseases. "The first-of-its-kind pivotal trial of an mRNA-based pandemic influenza vaccine underscores the potential of this technology to reshape how we confront emerging pathogens," said Richard Hatchett, CEO of CEPI. 

 

"If successful, these efforts could transform our ability to respond swiftly and equitably to one of the world's most enduring threats."

 

The Phase 3 study will enroll around 4,000 healthy adults aged 18 and older across the US and UK, evaluating both safety and immune response. Regulators are also expected to consider data from Moderna’s seasonal flu vaccine candidate, mRNA-1010, which is already under review in multiple regions including the U.S., EU, Canada, and Australia.

 

Public health officials in the UK emphasized continued vigilance despite currently low human risk. 

 

"Although the current risk to the human population of avian influenza remains low, the virus continues to evolve and spread in birds and various animal hosts in the UK and elsewhere," said Richard Pebody, Director of Epidemic and Emerging Infections at the UK Health Security Agency (UKHSA). 

 

"UKHSA remains alert to the potential that this pathogen could adapt to spread from person to person, and will continue to monitor all available data. This important initiative to trial a new mRNA pandemic influenza vaccine is a key step towards further strengthening our ability to protect people against future influenza pandemics."

 

If approved, Moderna has also pledged that 20% of its H5 pandemic vaccine manufacturing capacity will be reserved for low- and middle-income countries at affordable prices under its agreement with CEPI—positioning the program as both a commercial and global health security effort.