Science thoughts

Dear steemians, I am very glad to be here. I was thinking of how to make humans live longer by alleviating diseases. This came to mind though I doubt it could be done. I am wondering whether it's possible to create a bacteriophage which has been weakened to an extent and inject it to an individual to reduce bacterial infections since bacteriophages attack and ingest bacteria. It's crazy I know...just thinking. i would love to know your views on this.