Innovative Needle-Free, Live-Attenuated Influenza Vaccines Offer Broad Protection

Researchers at The University of Hong Kong, in collaboration with the Center for Immunology & Infection, have achieved a groundbreaking development in influenza vaccine technology. They have created two novel live-attenuated influenza vaccines (LAIV) that can be administered without needles and provide broad protection against a variety of human and bird flu virus subtypes.

These advanced vaccines hold promise for the future of universal influenza immunization, stimulating strong immune responses across different strains, including those from avian species that could pose pandemic threats. Their success has been recognized internationally, earning multiple patents and prestigious awards at the 50th International Exhibition of Inventions Geneva 2025, such as the Saudi Innovation Excellence Prize and two Gold Medals.

Traditional influenza vaccines mainly target specific circulating strains and need annual reformulation, often with fluctuating effectiveness. Moreover, existing vaccines do not adequately protect against animal-origin influenza viruses, which could lead to future pandemics. In response, the HKU research team developed two innovative strategies.

The first involves inserting a human gene (α-1,3-galactosyltransferase) into the influenza virus genome. This modification causes infected cells to display α-Gal epitopes, which human antibodies recognize, boosting immune responses such as antibody production, cytotoxicity, opsonization, and phagocytosis.

The second strategy introduced numerous silent mutations into the virus, changing its genetic code to resemble that of avian viruses. This attenuation method makes the virus safe for use as a live vaccine in mammals while retaining its ability to replicate in chicken eggs, facilitating manufacturing. Both approaches have demonstrated efficacy in preclinical studies, providing broad protection in mouse models against various influenza A subtypes, including H1N1, H3N2, H5N1, and H7N9.

A key advantage of these vaccines is their intranasal, needle-free delivery, which induces mucosal immunity in the respiratory tract, offering additional protective benefits. According to Professor Leo Poon Lit-man, this method also reduces vaccination fears, particularly among children, potentially decreasing vaccine hesitancy.

Looking ahead, the team plans to utilize Hong Kong Jockey Club Global Health Institute resources to further develop these vaccines, including conducting research in compliance with Good Laboratory Practice standards. Collaborations with organizations like the International Vaccine Institute will support ongoing efforts to bring these innovations into clinical application, aiming for a future where influenza vaccination offers comprehensive, broad-spectrum protection.

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