Moderna, after losing US funding, rebounds to start mRNA bird flu vaccine trial

Moderna Initiates Phase 3 Bird Flu Vaccine Trial After Funding Loss

Moderna has initiated a Phase 3 clinical trial for its mRNA-1018 bird flu vaccine, despite facing a significant loss of U.S. government funding. The trial aims to enroll approximately 4,000 healthy adults in the U.S. and U.K. to assess the vaccine's safety and ability to provoke an immune response. This development follows the Trump administration's cancellation of a contract in May 2025, which had previously provided Moderna with $176 million in 2024 and an additional $590 million in January 2025. The Coalition for Epidemic Preparedness Innovations (CEPI) subsequently offered up to $54.3 million to support the vaccine's development, with Moderna committing 20% of its manufacturing capacity for low- and middle-income nations in a pandemic.

• Moderna has commenced a Phase 3 trial for its mRNA-1018 bird flu vaccine, enrolling around 4,000 healthy adults in the U.S. and U.K. The study's primary objective is to assess the vaccine's safety profile and its ability to elicit a robust immune response, marking a critical step in preparing for a potential human H5 influenza outbreak.
• The trial proceeds despite the Trump administration's cancellation of a substantial U.S. government contract in May 2025, which had previously allocated $176 million in 2024 and an additional $590 million in January 2025 for mRNA vaccine development. The Coalition for Epidemic Preparedness Innovations (CEPI) stepped in, providing up to $54.3 million to ensure the bird flu vaccine's continued development.
• As part of the agreement with CEPI, Moderna has pledged to dedicate 20% of its manufacturing capacity to supply low- and middle-income countries with affordable bird flu vaccines should a pandemic occur. This commitment underscores a public-private partnership approach to global health preparedness, leveraging mRNA technology for widespread access.

The Global Public Health Imperative for an H5 Influenza Vaccine

The global epidemiological landscape of H5 influenza has undergone dramatic transformation since 2020, with unprecedented geographic expansion and increased circulation intensity. From 2017 to September 2020, H5N1 virus high-risk areas and cases in wild birds and poultry were limited primarily to Asia and Europe. However, from October 2020 to March 2025, H5N1 cases experienced rapid expansion, with high-risk areas for virus circulation spreading to almost the entire world. By June 2023, H5N1 had caused severe influenza in two persons and killed millions of birds and hundreds of mammals with aquatic lifestyles globally.

Regional surveillance data reveals significant variation in detection rates and temporal trends across different geographic areas. In the Poyang Lake region of China, comprehensive surveillance from February 2017 to June 2024 involving 7,570 poultry and environmental samples demonstrated an overall avian influenza positivity rate of 40.1%, with dramatic increases over time from 16.9% poultry positivity in 2017 to 69.4% by 2024. Similarly, environmental positivity rates increased from 15.5% to 77.7% over the same period. In Ghana during 2021-2022, surveillance of 2,847 samples revealed a 2.2% positivity rate for HPAIV H5N1, while in Upper Egypt during 2023-2025, HPAI-H5N1 was detected in 16% of broiler flocks with 25%-50% mortality rates.

The current global situation is dominated by HPAI H5N1 clade 2.3.4.4b viruses, which have notably expanded their geographical reach, affecting numerous countries, diverse avian species, and now mammals. In Europe, 120 million birds died or were culled during the 2020-2025 period, with HPAI H5 detected year-round for the first time in 2022. The recent outbreak in the United States has spread among twelve states with transmission to dairy cattle farms and three human cases. Risk mapping analyses reveal notable ecological suitability for HPAI H5 circulation across Europe, Asia, and the Americas, with significant expansions of at-risk areas post-2020, indicating continued high potential for further geographic spread and sustained circulation.

Moderna's Bold Bet: mRNA Bird Flu Vaccine Navigates Funding Shifts

Moderna's decision to advance its mRNA-1018 bird flu vaccine into Phase 3 trials, despite a significant withdrawal of U.S. government funding, is a powerful statement about the company's strategic direction and the enduring potential of mRNA technology. This move signifies a crucial expansion of the mRNA platform's application beyond its initial, highly successful deployment against COVID-19. Research has consistently highlighted mRNA vaccines for their high potency, safety, efficacy, and rapid development capabilities, making them ideal candidates for addressing novel and emerging viral threats. By targeting bird flu, Moderna is not only diversifying its pipeline but also reinforcing the versatility and robustness of its core technology.

The funding landscape surrounding this trial is particularly telling. The cancellation of a substantial U.S. government contract could have derailed the program, yet Moderna's commitment, bolstered by support from CEPI, demonstrates a strategic pivot. This shift underscores a growing emphasis on global health equity, with Moderna pledging 20% of its manufacturing capacity for low- and middle-income nations in a pandemic scenario. This commitment positions the company as a proactive partner in global health security, addressing concerns about equitable access that arose during previous pandemics.

However, this ambitious undertaking is not without its challenges. The financial burden of a large-scale Phase 3 trial, now largely self-funded, represents a significant investment. While mRNA vaccines have a strong safety record from COVID-19, demonstrating comparable safety and immunogenicity for a new indication like bird flu will be critical for regulatory approval and public acceptance. Furthermore, the dynamic nature of influenza viruses means that continuous monitoring of viral evolution and potential competition from other vaccine platforms will be essential. Ultimately, this trial will be a key test of mRNA's ability to deliver on its promise for broader infectious disease prevention and Moderna's resilience in navigating complex funding and public health landscapes.