Its been a while since I traveled by airplane, but I used almost always end up with at least sore nose/throat everytime I did . I guess the systems have improved a lot over the years , there getting away now from engine bleed air ,which comes with a whole host of potential issues for health.
Sub micron filters can scrub most of the nasties out , but thats never going to reach 99.97% effective inside the cabin unless everybody exhales directly into the return/filter system ,which they dont . The whole subject of cabin air quality is something the air industry has played down the signifigance of since way early on . One thing for sure is the whole model the aviation industry is based on means its planes in the sky or bust, so the whole industry is setup on a knife edge . The other issue is if things relating to Covid-19 worsen and aviation needs to be curtailed globally ,like in the days after Sept11 we could see a domino effect on climate.
I was looking at making a few small orders off ebay , but some places 'seller is away until date' seems to being pushed out a little longer than usual , I dont shop with Amazon ,but hearing their supply chain is in difficulty lately might be another indication more serious implications are coming down the pipeline.
Its scarey that the virus has taken such a fast a hold in Italy , in a region close enough to the geographical centre of the EU and with close connections to neighbouring countries .