Either you're using a different definition of bad, or you've got some information I don't have, or you're wrong.
What do you mean by this? Perhaps, that some of them are bad and thus shouldn't be used by the general population?
>No, he meant that we don't use vaccines that are bad.
By "he", you mean me?
Making a claim about the safety of pre-approval vaccines is misleading because it's claiming one uncontroversial true thing ("some vaccines in development are found to be net negative in trials and do not progress further") that sounds superficially similar to a scary untrue thing ("getting vaccinated by your doctor with an approved vaccine may be net negative across the population") and hoping everyone else will confuse the two.
In this case "some vaccines are bad" was clearly intended to be an ambiguous statement, otherwise it would have been more detailed about which exact vaccines were bad.