https://www.the-microbiologist.com/news/researchers-pioneer-novel-needle-free-live-attenuated-influenza-vaccines-with-broad-protection/5833.article

A research team from the University of Hong Kong has developed a broad response live-attenuated influenza vaccine (LAIV) by inserting specific genes into the influenza virus to activate natural human antibodies, thereby enhancing the vaccine-induced immune response. In addition, the researchers  introduced silent mutations into human influenza viruses, shifting their codon usage from that of a human  to that of an avian influenza virus-like pattern, making it safer for use as an LAIV.

The vaccine may be applied through inhalation through the nose and thus may alleviate the fear of vaccination in young children.