When combined with an immune-boosting substance called an adjuvant, low doses of an experimental vaccine against a strain of avian influenza (H9N2) provoked a strong antibody response in human volunteers, report scientists supported by the 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, and was led by Robert L. Atmar, M.D. The results are now online in Clinical Infectious Diseases.
"The results of this clinical trial add to the growing body of information demonstrating the potential value of adjuvanted avian influenza vaccines," says NIAID Director Anthony S. Fauci, M.D. An adjuvant is a substance that is added to a vaccine to boost the body's immune response to the vaccine's antigen. "In the event of an influenza pandemic, adjuvanted vaccines could provide a way to extend a limited vaccine supply to more people," he adds.
In 1999, two children in Hong Kong became infected with H9N2, a strain of avian influenza that had not previously been detected in humans. Humans have little or no natural immunity to a virus--such as H9N2 or the more deadly H5N1 avian influenza--that historically has circulated only in birds. If H9N2 or H5N1 were to acquire the ability to spread easily from person to person, an influenza pandemic could result, health experts say.
In 2004, NIAID directed Novartis Vaccines and Diagnostics (formerly Chiron Corporation) to produce 40,000 doses of an experimental H9N2 vaccine at its vaccine manufacturing facility in Siena, Italy. Some of the vaccines were formulated with Novartis's MF59 adjuvant. (See http://www3.niaid.nih.gov/news/newsreleases/2004/h9n2.htm.)
Dr. Atmar and his colleagues tested the vaccines in volunteers
Contact: Anne A. Oplinger
NIH/National Institute of Allergy and Infectious Diseases