University of Maryland’s Intranasal Vaccine Shows Promise Against H5N1

Researchers at the University of Maryland School of Medicine have reported promising results from an early-stage clinical trial of an experimental intranasal vaccine targeting the H5N1 “bird flu.” Conducted by the Center for Vaccine Development and Global Health (CVD), the study indicates that the intranasal vaccine may generate a robust immune response against multiple strains of the virus. The findings were published in the journal Nature Communications on March 15, 2025.

The study involved 40 healthy adult volunteers who were randomly assigned to receive varying doses of the H5 flu vaccine, which included BlueWillow’s NanoVax W 80 5EC adjuvant. Control groups received either a placebo or a high dose of the H5 vaccine without the adjuvant. Six months post-vaccination, all participants received an intramuscular booster shot of the H5 flu vaccine.

Dr. Justin Ortiz, a professor of medicine at UMSOM and the study’s corresponding author, emphasized the critical need for effective strategies to combat potential pandemics. “The spread of H5N1 influenza in animals with spillover into human populations globally highlights the critical need for effective countermeasures to protect our communities,” he stated.

Current intramuscular vaccines primarily elicit systemic immune responses, which can effectively reduce symptomatic illness when matched to circulating strains. In contrast, the intranasal vaccine aims to stimulate immunity at the site of infection, potentially diminishing transmission rates among individuals.

The trial results indicated that the NanoVax H5 intranasal vaccine was safe and well-tolerated among participants. Notably, those who received the nasal vaccine demonstrated strong immune “priming,” enhancing their immune systems’ readiness to respond to infections. This priming effect was particularly significant after the subsequent intramuscular booster dose.

Dr. Meagan E. Deming, co-lead author of the study, noted that the vaccine successfully enabled the immune system to recognize various versions of the H5N1 virus, an important factor given the virus’s mutating nature. Additionally, the use of the adjuvant may allow for lower vaccine doses, potentially increasing the availability of vaccine stocks during outbreaks.

The study found that volunteers receiving the adjuvanted H5 vaccine exhibited heightened immune activity, including elevated levels of protective antibodies, such as IgG and IgA, along with enhanced memory immune cells and an improved capacity to eliminate infected cells. Dr. Franklin R. Toapanta, another co-lead author, highlighted the implications of these findings, stating, “These findings demonstrate successful mucosal priming and the potential for broad cross-clade immunity.”

The research aligns with global health priorities to develop vaccines that can effectively reduce the transmission of influenza and offer broader protection against emerging strains. Dr. Mark T. Gladwin, Dean of the University of Maryland School of Medicine, underscored the importance of further research into mucosal immune biomarkers and alternative immune correlates of protection. Such research may significantly expedite the development of intranasal influenza vaccines.

As the threat of H5N1 and other influenza viruses continues to loom, the potential of this intranasal vaccine could be a crucial development in pandemic preparedness, offering a practical and scalable approach to safeguarding public health. Further research will be essential to explore the full capabilities and applications of this innovative vaccine technology.