It sounds like your thinking of a live-attenuated vaccine. An mRNA vaccine could not cause this. These is nothing more than a coincidence

Even if we assume that you somehow can be infected by a vaccine that doesn't contain the virus, if your colleague got infected 2 days ago, it's relatively unlikely a contact person would already have gotten infected from them and be showing symptoms.

With >300k reported and many more unreported cases, her daughter may have got it from anyone or it may be a seasonal fever of April. This is a simple confirmation bias.