H9N2 vaccine shows potential

An adjuvant is a substance that is added to a vaccine to boost the body's immune response to the vaccine's antigen.

The avian influenza vaccine provoked a strong antibody response in human volunteers, according to scientists supported by the US National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

The clinical trial of 96 adults was conducted at the NIAID-supported Viral Respiratory Pathogens Research Unit at Baylor College of Medicine, Houston.

“The results of this clinical trial add to the growing body of information demonstrating the potential value of adjuvanted avian influenza vaccines,” said NIAID Director Anthony Fauci. “In the event of an influenza pandemic, adjuvanted vaccines could provide a way to extend a limited vaccine supply to more people,” he added.

In the trial, a single inoculation of adjuvant-containing H9N2 vaccine, even at the lowest dosage, generated a good antibody response. By comparison, the seasonal flu vaccine contains 15 micrograms each of three different circulating flu strains - much higher than the 3.75 micrograms of H9N2 flu virus contained in the lowest dose vaccine tested in this trial. A single dose of the adjuvanted H9N2 vaccine was as good as two doses of the vaccine without adjuvant.