A new universal flu vaccine has been shown to protect against influenza B viruses in cell and mouse models. The corresponding study was published in Biomaterials.
Influenza epidemics pose a major threat to public health. Influenza A is the most common flu virus, making up around 75% of confirmed flu cases. It is also the only type of virus that can cause a pandemic; bird flu and swine flu were Influenza A viruses.
While influenza B tends to make up around 25% of confirmed flu cases, between 2019 and 2020, it caused over 50% of clinical infection cases. The virus causes a milder form of flu than influenza A, and adults are more often symptomatic than children.
Influenza B has two genetically distinct lineages, known as 'Victoria' and 'Yamagata', that trigger different immune responses. While seasonal flu vaccines attempt to tackle both lineages, they’re often limited in efficacy due to viral mutations, and thus need to be reformulated regularly.
Researchers in the present study developed a double-layered protein nanoparticle vaccine to overcome this limitation and protect against both strains as they evolve. Dr. Baozhong Wang, senior author of the study and Distinguished University Professor in the Institute for Biomedical Sciences at Georgia State University, said:
"In this study, we generated structure-stabilized HA stalk antigens from influenza B and fabricated double-layered protein nanoparticles as universal influenza B vaccine candidates. [...] We found that layered protein nanoparticles incorporated with structure-stabilized constant antigens have potential as a universal influenza vaccine with improved immune protective potency and breadth."
The researchers tested the vaccine in cell cultures and in mice. In cell studies, the protein nanoparticles effectively activated dendritic cells, which induced a protective immune response against pathogens. Meanwhile, from tests in mice, the researchers confirmed that the vaccine was safe, biocompatible, biodegradable, and highly immunogenic.
The researchers now hope to combine the nanoparticles for influenza B from this study with those from previous work for influenza A. In doing so, they hope to create a multivalent universal influenza nanoparticle vaccine that could protect against both influenza A and B.
Sources: Science Daily, Biomaterials