(Side note: You wouldn’t use CRISPR nor HeLa cells, but rather traditional cloning techniques + any of a number of other cell lines traditionally used for recombinant protein production. But that’s tangential to your question.)
I’m far from an expert here, but anything involving cell culture is generally thought to be pretty expensive. The media is expensive, other culture conditions can add to the cost as well (e.g. continuous supply of CO2 for mammalian cells), transfection reagents are expensive, and you have to expend a lot of effort keeping out bacterial/fungal/viral contamination. The inherent variability in biological processes means that you have to deal with batch-to-batch variability in your recombinant protein product, which might mean added expenses in monitoring and analysis (and headaches dealing with regulatory agencies). Basically, cells are fickle and require a lot of babysitting and care.
mRNA vaccines don’t have any of these issues, because cell culture isn’t involved for the most part. Most everything is done in vitro — in that sense, mRNA vaccine production is more like chemistry than biology. And, therefore, it’s more similar to peptide-based vaccine production (chemical synthesis) than protein-based vaccine production is — which, again, is why it’s weird to contrast peptide- and protein-based vaccines together against mRNA vaccines.
(Side note: You wouldn’t use CRISPR nor HeLa cells, but rather traditional cloning techniques + any of a number of other cell lines traditionally used for recombinant protein production. But that’s tangential to your question.)
I’m far from an expert here, but anything involving cell culture is generally thought to be pretty expensive. The media is expensive, other culture conditions can add to the cost as well (e.g. continuous supply of CO2 for mammalian cells), transfection reagents are expensive, and you have to expend a lot of effort keeping out bacterial/fungal/viral contamination. The inherent variability in biological processes means that you have to deal with batch-to-batch variability in your recombinant protein product, which might mean added expenses in monitoring and analysis (and headaches dealing with regulatory agencies). Basically, cells are fickle and require a lot of babysitting and care.
mRNA vaccines don’t have any of these issues, because cell culture isn’t involved for the most part. Most everything is done in vitro — in that sense, mRNA vaccine production is more like chemistry than biology. And, therefore, it’s more similar to peptide-based vaccine production (chemical synthesis) than protein-based vaccine production is — which, again, is why it’s weird to contrast peptide- and protein-based vaccines together against mRNA vaccines.