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New Approach for Influenza Vaccination Shows Promise in Early Testing
According to a report from the National Institutes of Health (NIH), a new approach for immunizing against influenza has elicited a more potent immune response and broader protection than the currently licensed seasonal flu vaccines when tested in animals. The new vaccine concept, which was developed by scientists at the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, represents an important step forward in the quest to develop a universal flu vaccine — one that would protect against most or all influenza strains without the need for an annual vaccination.
The new research was published online in Nature.
The scientists designed an experimental vaccine featuring the protein ferritin, which can self-assemble into microscopic nanoparticles, as a key component. Ferritin was fused genetically with hemagglutinin (HA), the protein found on the surface of the influenza virus, resulting in a nanoparticle with eight protruding viral spikes. Using this as the basis for the vaccine antigen, the researchers created an experimental vaccine using HA from a 1999 strain of H1N1 influenza virus and evaluated its ability to stimulate an immune response in mice.
A single dose of the experimental vaccine both with and without the use of an adjuvant triggered an immune response in the mice comparable with two doses of the currently licensed seasonal flu vaccine. The experimental vaccine was also active against a wider range of H1N1 influenza virus strains than the licensed vaccine.
The researchers also tested the experimental vaccine’s ability to protect ferrets from infection with a 2007 strain of H1N1 influenza virus — a strain the vaccine had not been specifically designed to prevent. One day after exposure to the virus, the ferrets that had received the experimental vaccine had significantly lower influenza virus levels than those that were not immunized.
According to the study's authors, the novel vaccine concept works by stimulating antibodies that “hitch” themselves to the parts of the influenza virus that stay consistent across different strains. Although further testing is needed, the HA–ferritin nanoparticle approach shows promise for the development of more broadly protective vaccines for influenza as well as for other infectious diseases, the authors note.
Source: NIH; May 22, 2013.