A late-stage clinical trial has commenced for an mRNA vaccine designed to combat a bird flu variant affecting numerous animals and sporadically humans across the globe.
This emerging vaccine could prove vital if a bird flu outbreak escalates to pandemic levels.
About a year passed after the initial COVID-19 cases before vaccines against the SARS-CoV-2 virus became available. By that point, millions had perished globally, and economies suffered severe impacts. For a potential bird flu pandemic, response times could be quicker, thanks to an mRNA vaccine that might gain approval and be prepared for deployment. A phase III trial of this vaccine is now launching in the United Kingdom and the United States.
Experts warn that an influenza pandemic represents the most probable next global health crisis, emphasizing the need for thorough readiness, according to a representative from the UK Health Security Agency.
The primary concern stems from an H5N1 bird flu variant known as clade 2.3.4.4b, which has proliferated among wild birds worldwide since emerging about ten years ago, even extending to Antarctica. Infections have occurred in various wild mammals via contact with birds, and the virus has frequently infiltrated poultry operations. In the US, it has been detected in dairy herds.
Over 100 human infections have been reported since 2024, though no signs of human-to-human transmission have emerged yet. As long as the virus persists in circulation, the danger persists.
A spokesperson from Moderna highlighted that while the exact timing and intensity of the next pandemic remain unpredictable, the ongoing presence of influenza viruses in animals and their potential to mutate underscore the importance of readiness.
Moderna’s mRNA-1018 vaccine for H5N1 has completed initial and intermediate trials without notable safety issues. The current phase III study will recruit 3000 participants in the UK and 1000 in the US.
Typically, vaccine trials assess efficacy directly, but given the absence of widespread human transmission of H5N1, this study will evaluate the robustness of participants’ immune reactions. Prior trial data indicate a robust response, according to the company.
The trial focuses on individuals over 65 and those employed in poultry handling, as they face heightened risks from bird flu.
Certain nations maintain reserves of traditional H5N1 vaccines; for example, the UK holds 5 million doses. These are produced using chicken eggs, similar to many seasonal flu shots. This method poses challenges for quick production increases or adjustments if the virus mutates substantially.
In comparison, mRNA vaccine manufacturing can expand swiftly and adapt easily to viral changes, offering key benefits for pandemic response, as noted by health officials.
Funding for the trial comes from the Coalition for Epidemic Preparedness Innovations, supported by over 30 nations and various groups. This organization intervened after the US government reduced support for mRNA vaccine initiatives.
Nations like the UK and US might also implement H5N1 vaccinations for livestock, particularly birds. This strategy has been employed elsewhere, with research in France demonstrating that immunizing ducks significantly lowered farm outbreaks.
