Jet aircraft have been flying for decades, if there was some long term health issue to every one we would know by now.
There is an issue with mechanical failures that results in contamination of cabin air. This in some case adveresly affects some people. This is no different to many other problems in society. We have enough statistics over the length of time now to say the problem is statistically insignificant.
Unfortunate for the people it does affect, sadely they will not be the same again, but the aircraft industry works on affordable safety. If you can come up with some numbers showing effects are significant for total number of people flying, then something will be done about it.