Moderna's Bird Flu Vaccine Just Launched Without Washington. Here's What That Actually Means.

Yesterday, April 21, Moderna dosed the first participants¹ in a Phase 3 trial of its mRNA-based H5N1 bird flu vaccine, mRNA-1018. About 4,000 healthy adults across the U.S. and UK will be enrolled. This is, by any standard, good news for pandemic preparedness. It is also the product of one of the strangest institutional journeys in recent public health history, and understanding that journey matters a lot more than the press releases suggest.

Let me walk through what happened. In January 2025, the outgoing Biden administration awarded Moderna $590 million through BARDA² to accelerate mRNA pandemic flu vaccines, including an H5N1 candidate. Four months later, in May, the new HHS under Secretary Robert F. Kennedy Jr. terminated the contract³, with HHS Communications Director Andrew Nixon declaring that "continued investment in Moderna's H5N1 mRNA vaccine was not scientifically or ethically justifiable." By August, HHS had canceled all 22 BARDA-funded mRNA vaccine projects⁴, roughly $500 million worth, with Kennedy claiming these vaccines "fail to protect effectively against upper respiratory infections." This was stated despite the fact that Moderna's Phase 1/2 data showed 97.8% of participants achieved protective antibody levels⁵ after two doses.

So how is the Phase 3 trial running today? In December 2025, CEPI stepped in with up to $54.3 million⁶ to fund the pivotal study. The UK's NIHR is also supporting the trial⁷, with 75% of participants being recruited at UK sites. The U.S. government, which initiated and funded the program, is now a bystander.

The conventional take on this story goes one of two directions. The optimistic version: the system worked, private actors and multilateral coalitions filled the gap, resilience prevailed. The pessimistic version: pandemic preparedness has been privatized, accountability has been lost, equity will suffer. I think both takes are partly right and partly wrong, and the truth sits in an uncomfortable middle that neither camp wants to inhabit.

Start with what the optimists get right. Moderna's trial is running. It would not be running if the only funding pathway were through U.S. federal appropriations, because those appropriations were killed by ideological opposition to mRNA technology, not by fiscal prudence or scientific assessment. The existence of CEPI as an alternative funder prevented an outright loss of a critical preparedness asset. FDA regulatory authority over data disclosure, trial reporting on ClinicalTrials.gov, and the licensure process all remain fully intact regardless of who funded the work. These are not trivial safeguards. They mean Moderna must submit complete clinical data packages for any approval, whether HHS paid for the trial or CEPI did.

But here is where I part company with the sanguine interpretation. The CEPI agreement includes a provision that Moderna will allocate "20% of its H5 pandemic vaccine manufacturing capacity for timely supply to low- and middle-income countries at affordable pricing"⁸. That sounds reassuring. The problem is that we have run this exact experiment before, and it failed.

During COVID-19, CEPI funded multiple vaccine candidates with explicit equitable access commitments. The results were, to put it mildly, poor. A People's Medicines Alliance analysis found that CEPI's early agreements with Moderna "contained no licensing or step-in rights, effectively making their commitments toothless."⁹ By February 2022, just 1% of Moderna's COVID vaccine had been delivered to low-income countries. The broader COVAX initiative, which CEPI co-led, is widely acknowledged to have failed¹⁰: by end of 2021, over 76% of people in high-income countries had received a dose, compared to only 8.5% in low-income countries. WHO Director-General Tedros Ghebreyesus put it starkly in January 2021: high-income countries had administered 39 million doses while one low-income country had received exactly 25¹¹.

Now, CEPI has reformed its processes since then. Its newer agreements are structured more robustly than its early COVID-era step-one contracts. But 20% of manufacturing capacity is a ceiling, not a floor, and the phrase "affordable pricing" is not a defined price cap. When an actual pandemic hits and wealthy governments start placing advance purchase orders at premium prices, a voluntarily pledged percentage of capacity has historically buckled under commercial pressure. CEPI itself acknowledged⁶ that its COVID equitable access provisions "were not designed for, and did not achieve, real-time global allocation during an acute emergency."

I want to be precise about what this means for the current H5N1 situation. The trial is enrolling healthy adults 18 and older in the U.S. and UK, with researchers prioritizing individuals over 65 and poultry workers¹². That is a sensible trial design for the populations most at risk in those two countries. But H5N1's zoonotic emergence risk is concentrated among agricultural workers in Southeast Asia, where most of the world's roughly 1,000 reported human cases with ~50% fatality¹³ have historically occurred. No existing binding instrument compels Moderna to study or prioritize deployment to those populations. BARDA's original contract didn't either, it should be said. But the absence of public-sector direction makes it even less likely that commercial development will address the populations where the pandemic risk is highest.

The deeper structural problem is this: BARDA was created in 2006 precisely because Congress recognized that "without a commercial market to encourage the development of vaccines"¹⁴ against CBRN and pandemic threats, "the government has had to create a market." The entire institution existed to solve a market failure. By 2020, BARDA had helped obtain FDA approval for at least 50 products¹⁵ and built a pipeline of roughly 80 countermeasures. It was not a perfect institution. The Strategic National Stockpile was depleted after H1N1 and not replenished. The U.S. H5N1 vaccine stockpile was already potentially mismatched to circulating clade 2.3.4.4b strains before the current administration took office. Government pandemic preparedness has been imperfect. But imperfect governance and no governance are different categories of problem, and what Kennedy's HHS has done is not reform. It is abandonment of the mission based on anti-mRNA ideology contradicted by the clinical data.

Former BARDA director Rick Bright warned that this creates "a huge strategic failure that will be measured in lives lost during times of crisis."¹⁶ Former assistant secretary for pandemic preparedness Chris Meekins called it a potential "national security vulnerability." These are not partisan figures; they served across administrations.

So where does this leave us? I think the honest assessment is: (1) CEPI stepping in to fund this trial is genuinely better than the trial not happening, (2) FDA regulatory authority provides real constraints on data quality regardless of funding source, but (3) the multilateral instruments now carrying the load have a documented record of failing on equity under stress, and the 20% capacity commitment in the current CEPI-Moderna agreement is weaker than what would be needed to prevent a repeat of COVID-era allocation disparities. The U.S. government's exit from pandemic vaccine development is not being adequately replaced.

The thing to watch is not whether Moderna's H5N1 vaccine works. The Phase 1/2 data is encouraging and mRNA platforms are well-proven. The thing to watch is what happens if H5N1 acquires efficient human-to-human transmission. The CDC still assesses general public risk as low¹⁷, but the virus is now circulating in more species across more continents than ever before, and U.S. surveillance varies dramatically between states¹⁸. When the moment arrives, will deployment decisions be made by public health authorities with a mandate to protect populations based on epidemiological need, or by a company allocating supply based on who can pay the most, the fastest? The CEPI agreement is a partial answer to that question. COVID showed it is not a sufficient one. I expect that if H5N1 goes pandemic before stronger binding procurement agreements are in place, we will see the same dose-hoarding pattern by wealthy nations that defined 2021, and the 20% capacity pledge will prove as enforceable then as CEPI's COVID commitments proved in practice.