Why are intranasal vaccines so effective against respiratory diseases?
a.They kill all viruses as they are inhaled.
b.Immunoglobulin A is produced at the site of virus entry.
c.Given intranasally, they work with nasal mucus to increase protection.
d.It is much easier to give them intranasally than subcutaneously or IM.
b.Immunoglobulin A is produced at the site of virus entry.