Can any doc explain why can't people with asthma get the nasal spray flu vaccine?

Asthma flare up: The nasal vaccine is weakened but living flu germ.To get into your system and produce a vaccine response, it must cross through the lung tissue. In doing so it causes a mild inflammation of the lung tissue and can trigger an asthma attack. I had a 8 yo have his first and only asthma attack 2 days after the nasal flu vaccine was given. I now won't offer this at my office.