That argument is empirically false, as there have been multiple medications and vaccinations which did widespread harm.
Granted, nearly all of them occurred 30+ years ago. However I don't think we should ever claim we've advanced to the point where we _know_ that there are _no_ medications or vaccinations that are causing problems we aren't aware of yet, especially given how long it might take for those problems to manifest themselves.
Not an argument against vaccination at all, just an argument for intellectual humility.