I'm confused. Where does this say the vaccine is mRNA? The Valneva VLA15 website explicitly states "VLA15 is a multivalent recombinant protein vaccine" [1], and the linked press release calls it a "investigational multivalent protein subunit vaccine". Does nobody actually read these things?
See [2], "Subunit Vaccines".
[1] https://valneva.com/research-development/lyme-disease/
[2] https://www.niaid.nih.gov/research/vaccine-types