Scientists have developed a candidate vaccine to protect people against a possible outbreak of H7N9 bird flu. The preliminary development would make it easy to ramp up vaccine production for larger trials and in the case of an epidemic.
Avian influenza A (H7N9 ) is a subtype of flu viruses found in birds. H7N9 virus had never been seen in either animals or people until it was discovered in March last year in 2013. Most patients affected by the disease become severely ill. The flu is not known to spread from person-to-person contact but has been confirmed to affect people who have come into contact with infected birds.
The World Health Organization reported 139 cases of H7N9 flu as of late April. More than 20 percent of these cases have died. Robin Robinson, deputy assistant secretary for preparedness and response in the U.S. Department of Health and Human Services, said, “The vaccine described in this study is one of more than 150 medical countermeasures -- drugs, vaccines, and diagnostics -- the Biomedical Advanced Research and Development Authority has in the development pipeline in our quest to protect health during emergencies.”
Dr. Niranjan Kanesa-thasan, from Novartis Vaccines in Cambridge, Massachusetts, said that it is possible to achieve an effective vaccine against H7N9. He and his colleagues used synthetic virus technology after the virus’ gene sequencing to develop the vaccine. There were 400 people that developed antibodies to the H7N9 virus and participated in a trial to test the vaccine. However, actual effectiveness of the vaccine is not yet confirmed as participants were not exposed to real H7N9 virus.
Nevertheless, some antibody responses were reported to be similar to those seen in patients who survived the bird flu. To get an immune system response, the vaccine has to include an adjuvant called MF59. The adjuvant is used in the EU to improve flu vaccine effectiveness. MF59 is not yet approved in the U.S. Two doses are needed for the body to prime its immune system and to cue production of antibodies, Dr. Kanesa-thasan said.
Dr. Marc Siegel, associate professor of medicine at NYU Langone Medical Center in New York City, said that there has been no history of a bird flu mutation to the point of it becoming a human pandemic. Still, developing a vaccine is good preparation for a possible pandemic.
Robinson added, “We are working with multiple manufacturers, including Novartis, to develop H7N9 vaccine candidates, evaluate the candidates in clinical trials for safety and effectiveness, and stockpile H7N9 vaccine so our nation can respond quickly if this deadly virus emerges in the United States or becomes a pandemic.”