I think this is an unlikely scenario. What if they make a super deadly new pathogen emerge that is designed for that vaccine. So everybody without the vaccine gets super sick and likely dies. That way the people that easily trust and submit to their system is the ones who survive and most of the opposition is gone. People would be like OMG this vaccine is what save half the country and we have to take these otherwise we could die. It would be an effective way for them to take over and start a population that will submit to their plan is the part of the population they can use for their agenda.