Hi Jessica - this is great, very clear and specific.
I would echo the previous comment about observational learning - in prior work with the SCT framework, that has shown to be a really powerful motivator. If the film could weave in personal stories and experiences from a range of different target groups in seeking and obtaining the vaccine, that might help.
How do you intend to distribute the video? To make sure that it is seen by your target populations? It may be helpful to try to link distribution of the video with as many other "cues to action" as possible - to facilitate self-efficacy in actually obtaining the vaccine. For example, at the end of each video, list where and how an individual can go to get the vaccine, etc. Or have screenings of the video routinely at places where individuals can get the vaccine, etc.