Although the H7N9 virus, more commonly known as Avian flu, has yet to appear in the United States, it was identified in China in March 2013, and public health officials believe it may have pandemic potential. As of November 13, 2015, the World Health Organization has noted 681 confirmed cases with at least 275 deaths.
Recently, however, multiple candidate H7N9 pandemic influenza vaccines made from inactivated viruses have shown encouraging results, according to a recent article in The Journal of Infectious Disease.
Scientists from the National Institute of Allergy and Infectious Diseases (NIAID) successfully tested a prime-boost concept in a small clinical trial. Prime-boost vaccines operate in two stages. The "primer," derived from a live but weakened virus, is administered first, followed by a booster inactivated virus vaccine, which recalls a more robust immune response and induces strong immune memory.
Clinical researchers at the University of Rochester administered the prime-boost vaccines to 65 volunteers; 48 aged 18-49 years and 17 aged 50-70 years. Volunteers were given either one or two doses of the candidate live vaccine and then an inactive H7N9 vaccine 12 weeks later. Both were well-tolerated.
MedImmune, a Maryland company, created the live attenuated candidate H7N9 vaccine as part of a cooperative research and development agreement with NIAID. The dormant H7N9 vaccine was produced by Sanofi Pasteur of Swiftwater, Pennsylvania. The Biomedical Advanced Research and Development Authority of the Department of Health and Human Services also supported the study.
Further testing will determine whether the live-virus vaccine used alone would provide protection without the inactivated vaccine boost.
