Phage Therapy Gains Momentum Amid Rising Bird Flu Threat

The global threat posed by Highly Pathogenic Avian Influenza A (H5N1), commonly referred to as bird flu, is prompting renewed research into innovative treatments like phage therapy. With a mortality rate approaching 100%, bird flu has led to the loss of over 633 million birds worldwide in the last two decades, as estimated by the World Organization for Animal Health. The U.S. Department of Agriculture (USDA) estimates that from the onset of the current outbreak in 2022 to April 2025, more than 168 million birds will have died, largely due to culling practices. Cases have been reported in all 50 U.S. states, with spillover effects impacting various species, including domestic animals and marine mammals.

While human infections remain rare, they are occurring. The Centers for Disease Control and Prevention (CDC) reported 70 cases of human infections from March 2024 to May 2025, resulting in one death. This raises alarms not only due to the direct impact of the virus but also because of the potential for secondary bacterial infections that complicate severe cases of influenza. This scenario has spurred interest in bacteriophage therapy as a targeted approach to combat these bacterial complications while also developing vaccines against H5N1 itself.

CDC Insights on Bird Flu Risks

Gabriel Alvarado, a public affairs specialist at the CDC, emphasizes the potential for avian influenza viruses to cause a human flu pandemic, particularly as most individuals lack pre-existing immunity. He states, “These viruses have the potential to cause a flu pandemic in people if they were to gain the ability to more easily infect and spread efficiently between people.” The CDC’s assessment of the pandemic risk associated with these viruses indicates a moderate level of concern, underscoring the need for ongoing surveillance and proactive government responses.

Phage Therapy as a Solution

With the urgency to address avian influenza, researchers are looking at phage therapy not just as a means to tackle bacterial resistance but also as a potential vaccine platform against H5N1. Companies like Cytophage Technologies are developing phage-based vaccines utilizing filamentous phages that can continuously produce vaccine particles, effectively turning bacterial cells into “phage factories.” According to Steven Theriault, CEO of Cytophage, this method offers significant advantages: phages are self-adjuvanting, which enhances immune response and can eliminate the need for booster shots.

Theriault explains that the engineering of phage DNA to express stable viral epitopes is a critical step in this process, as it helps to mitigate the risks posed by the evolving nature of the virus. Moreover, the production efficiency of phage-based vaccines is notable, with the potential to generate 150 million doses in just seven days.

The safety profile of phages also adds to their appeal; they do not infect human or animal cells and cannot revert to pathogenic forms, setting them apart from traditional vaccine technologies.

Another innovative approach comes from PHIOGEN, where CEO Amanda Burkardt describes the development of “dual-action” phages. These phages not only target bacterial infections but also stimulate the immune system to prevent future infections. Burkardt’s team employs a proprietary technology platform that combines directed evolution and immune-relevant screening to identify phages that exhibit both antibacterial and immunogenic properties.

Advancements in Phage Research

Armata Pharmaceuticals is also making strides in phage therapy, focusing on creating pathogen-specific treatments for antibiotic-resistant infections. Sebastien Lemire, director of Discovery and Engineering at Armata, highlights the specificity of phages as a key advantage over broad-spectrum antibiotics. Their ongoing Phase II clinical trials for phage cocktails targeting Pseudomonas aeruginosa and Staphylococcus aureus showcase the potential of phages to penetrate biofilms and directly address bacterial infections that often follow viral illnesses.

Moreover, the integration of artificial intelligence in phage development is being explored by BiomX. CEO Jonathan Solomon notes that their BOLT platform combines vast libraries of natural phages with advanced computational tools to develop targeted therapies against chronic bacterial infections. This innovative approach could enable rapid responses to evolving threats like H5N1, providing timely treatments in pandemic scenarios.

The intersection of phage therapy and the ongoing threat of bird flu presents a compelling narrative of scientific innovation in public health. As researchers continue to explore the potential of phages, the hope is to create scalable, effective solutions not only for current infections but also for emerging threats that could impact global health security.