Avian Flu Vaccine with Longer Protection in Development

Scientist at Centers for Disease Control and Prevention harvests H7N9 viruses for research and testing by partners. (CDC.gov)

18 September 2017. A biotechnology company is designing a vaccine to protect against the newly emergent avian flu to provide more sustained protection like seasonal flu vaccines. EpiVax Inc. in Providence, Rhode Island is developing the vaccine, supported by a 5-year, $5.8 million award from National Institute of Allergy and Infectious Diseases, part of National Institutes of Health.

While other vaccines against avian flu are in development, including a candidate by EpiVax, these current vaccines against the H7N9 virus responsible for avian flu do not generate long-term immune responses, unlike seasonal flu vaccines that protect over an entire flu season with one injection. Public health authorities first spotted the human H7N9 virus in China in March 2013, which were believed to first infect poultry and later spread to humans in contaminated environments. Most patients infected with H7N9 experienced severe respiratory illness, with deaths occurring in about one-third of the cases.

While earlier H7N9 outbreaks were sporadic, in 2017 China is experiencing its largest epidemic to date. As of early September, World Health Organization counts 760 new cases in the current outbreak, bringing the total number of human infections to 1,558. While most cases result as before from poultry-to-human transmission, rare instances of human-to-human transmission are also being reported.

The EpiVax team led by company founder and president Anne De Groot is joined by researchers from University of Massachusetts medical school, University of Georgia, and the company Protein Sciences. The researchers plan to apply bioinformatics and molecular modeling to design enhanced hemagglutinin proteins found on the surface of the virus to stimulate  a longer-lasting response from the immune system to protect against H7N9 infections.

Those enhancements involve adding epitopes, or binding regions of antigens that stimulate production of antibodies, to the H7N9 hemagglutinin proteins. The added epitopes would resemble corresponding binding regions found in seasonal vaccines, but missing from wild type H7N9 viruses. These epitopes provide the memory capability of seasonal vaccines, enabling one injection to keep generating a response from T-cells in the immune system that last an entire flu season. Yet, the new vaccine would retain the ability to generate immune system responses specifically against H7N9 viruses.

The researchers plan a two-phase approach, with the first phase designing the new, enhanced hemagglutinin protein that retains the anti-H7N9 epitopes, but adds the more sustained responses, and testing the protein in lab cultures and with animals. In the second phase, the team plans to refine the vaccine to minimize opportunities for mutations, to maintain its potency over longer periods. The eventual outcome of the project is a vaccine candidate ready for final tests leading to an investigational new drug application with FDA.

EpiVax’s earlier vaccine protecting against H7N9 viruses by boosting its immune system response is currently in a clinical trial in Australia. That vaccine is supported by a $600,000 Small Business Innovation Research grant awarded a year ago by NIH.

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