1) Do you know the amount of hCG supposedly detected in the tetanuos vaccine in Kenya? When you figure that out, I'll tell you about the medical implausibility that it could have been an effective contraceptive or sterilization agent.
2) The deaths in Mexico were traced to bacterial contamination from an unknown source in the vaccine vials. It could have been a failure of manufacturing sterile technique or introduced by sloppy technique of those entering multi-dose vials many times with needles whle administering the injections.