I had respiratory failure 5 years ago 5 days after returning from my holiday to Spain on flight tom7777 . I asked the flight attendant on my next holiday how often they purge their air outlets? She went to the pilot and asked as she did not know. The pilot told her that they do not purge short haul any time! When the flight attendant asked why, I explained and she said that's was probably why we get throat and chest complaints all the time then? I started asking around and BA purge theirs after a set number of flights and sometimes use a natural disinfectant to kill 99.9% of the bugs that can hide there. Interested to hear if any one else has had similar?