Are there any shortcomings to it?-How do nasal vaccines work? Are they better than the injected ones?

Coroflu, a vaccine jointly developed and worked on by vaccine maker FluGen and the University of Wisconsin-Madison is India’s third prime vaccine candidate after COVAXIN and ZyCOV-D which uses a self-limiting version of existing influenza virus to stimulate immunity and spike up production of helpful antibodies in the system. The vaccine is expected to delve into human trials by the end of 2020.