New versions of a compound that can boost influenza vaccine potency are set for clinical trial.

The effectiveness of flu vaccines varies greatly year-to-year. The 18-month trial aims to determine if these compounds, called adjuvants, will produce a stronger, longer-lasting immune response in recipients, according to the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, which is funding the study.

Volunteers, currently being recruited, will be vaccinated with and without the use of the adjuvants. The results may help determine the best combination of vaccine and adjuvant that maximizes immunity. 

“NIAID not only supports the development of new vaccines, but also efforts to improve seasonal vaccines that are already available,” said Anthony S. Fauci, M.D., director of NIAID. “We hope this trial will increase our understanding of how adjuvants could help confer better protection from seasonal influenza.”

The two new adjuvants have shown promise in animal models, according to a statement about the trials released by the NIH.