A nasal spray delivering a broad-spectrum antibody has demonstrated potential to prevent infections from any flu strain in animal and preliminary human studies. Developed initially by Johnson & Johnson and now advanced by Leyden Labs, the spray could offer rapid protection during pandemics. Experts see it as a valuable tool for high-risk groups, though further testing is needed.
Influenza remains a persistent threat, with annual vaccines offering only moderate protection due to the virus's rapid evolution. To counter this, researchers have turned to a universal antibody approach. Johnson & Johnson created CR9114, an antibody that binds to a conserved part of the influenza virus, unaffected by mutations, enabling it to neutralize diverse strains.
Initial attempts to deliver CR9114 via injection proved ineffective, as little of the antibody reached the nasal passages—the primary entry point for the virus. In 2022, Leyden Labs licensed the technology and reformulated it as a nasal spray. Tests in mice and macaques exposed to various influenza A and B strains, including a 1933 human isolate, showed the spray prevented illness effectively.
Preliminary human trials involved 143 healthy volunteers aged 18 to 55. Administered twice daily, the spray maintained stable antibody levels in the nose without significant side effects. Analysis of participants' nasal mucus confirmed its ability to neutralize multiple strains, such as a 2013 bird flu variant that infected people in China.
The next phase will test the spray's efficacy by directly challenging treated individuals with live viruses. Linda Wakim, an immunologist at the University of Melbourne, notes limitations: "It may not be 100 per cent effective because the virus can enter the body via routes other than the nose, like the mouth." Still, she adds, "blocking nasal entry would still intercept the virus at a major access point for infection."
Wakim highlights its potential despite requiring twice-daily use compared to a single vaccine shot: "It could be a game changer for specific high-risk groups, such as immunocompromised individuals, frontline healthcare workers, or during a pandemic situation where rapid, short-term population protection is needed while vaccines are being developed or rolled out."
This development, detailed in Science Translational Medicine (DOI: 10.1126/scitranslmed.adz1580), underscores efforts to bolster defenses against evolving flu threats.
