Given your background in pharmacy I thought you may be well placed to answer the question about whether the nasal flu vaccine is suitable for Muslims. As a practicing Nurse I always get asked from various perspectives and I feel there is confusion in our community with regards to the following:
a) We are not "eating" it and the vaccine replicates in the nose
b) hHow can we form herd immunity and protect those that can't have it
c) Does the gelatine go through chemical changes making it pure no longer najis

I have a 5 year old who has never had the vaccine and I never felt that he was a risk to others because I always felt that I didn't want to put something najis into his body despite being a nurse and knowing the benefits of the flu vaccine and Alhamdulillah we have managed to stay well over the winter months without it. But I do get asked a lot and I wish I had a better answer!

Yes I’m aware of this re ruling. Scholars like Ayatullah Sistani leave it to the people themselves to make decision on whether complete transformations as taken place of the gelatine

I have done my research personally on this and I’m satisfied that indeed transformation does take place. But it’s a personal decision.