@frozen: mRNA vaccines have been tested for nearly 3 decades, none have passed FDA approval. Having one that works would be a goldmine for companies that invested the last 50 years in mRNA research. Hence why we now have “special” vaccines when they could’ve just made regular century-old egg-based vaccines, they saw an opportunity and went for it.
The drawbacks of mRNA treatment is also its strength. You can target specific viruses down to the variant, basically designer drugs that would be great for cancer treatment, you can target wayward cells that are very specific without making your body go completely autoimmune. But it means however in vaccines, as we now learned, that you have virtually no resistance against fast mutations and variants.