HHS cancels funding for Moderna’s candidate H5 avian flu and pandemic vaccines

In a startling pandemic preparedness development, Moderna yesterday announced that the US Department of Health and Human Services (HHS) has terminated a $590 million award it received in January for late-stage development of a candidate mRNA vaccine against H5 avian influenza and the development of other prepandemic vaccine candidates.

In the same announcement, Moderna reported positive interim phase 1/2 clinical data for its candidate vaccine targeting H5 avian influenza.

Contract awarded under Biden administration

Moderna received the HHS contract for an H5 vaccine in a $176 million base award in July 2024 amid a rising number of H5N1 infections in US residents, mostly agricultural works. On January 17 in the final days of the Biden administration, officials announced a $590 million contract to fund the development of vaccines against potential pandemic flu viruses.

Following the transition to the Trump administration, the HHS in early March signaled that it was evaluating the contract.

The move comes amid continued circulation of H5N1 in US dairy cattle, poultry flocks, wild birds, and other mammals, as well as animal outbreaks in other countries and sporadic H5N1 infections in a few Asian countries, such as Cambodia and Vietnam.

HHS secretary Robert F. Kennedy, Jr., is allied with groups that are skeptical about vaccines, especially mRNA formulations, which has shaped his recent policy decisions about COVID vaccines.

Moderna said it will explore alternatives for late-stage development of the H5 vaccine, consistent with its commitment to pandemic preparedness.

A blow to H5N1 preparedness

The announcement prompted concerns and warnings from several public health experts. Ashish Jha, MD, MPH, dean of the Brown University School of Public Health, said on X that the vaccine contract cancellation puts American lives at risk and that the attack on mRNA vaccines is absurd, given that they have been widely administered and studied, with a good safety and effectiveness track record.

“If Bird Flu starts spreading from people to people, we will come to regret this as the day we decided to put the lives of the American people at grave risk,” he said.

If Bird Flu starts spreading from people to people, we will come to regret this as the day we decided to put the lives of the American people at grave risk.

Krutika Kuppalli, MD, with the divisions of international medicine and infectious diseases at the University of Texas Southwestern Medical Center, on BlueSky called the move “stunningly shortsighted.”  She said the cancellation comes amid rising H5N1 threats, along with news yesterday of a fatal H5N1 case form Cambodia. “This will come back to bite us. Hard.”

Promising clinical trial results

Regarding the clinical trial findings, Moderna said the phase 1/2 study involved 300 healthy adults and evaluated at 2-dose regimen. It said the findings suggest a rapid, potent, and durable immune response. Pre-existing immunity was minimal at baseline, with 2.1% of participants showing hemagglutinin titers at a level considered to correlate with protection. At day 43, which was 3 weeks after the second dose, 97.9% of participants had a 44.5-fold increase in titers from baseline,

Stéphane Bancel, MBA, MS, Moderna’s chief executive officer, said, “While the termination of funding from HHS adds uncertainty, we are pleased by the robust immune response and safety profile observed in this interim analysis of the Phase 1/2 study of our H5 avian flu vaccine and we will explore alternative paths forward for the program.”