| They did. The AZ vaccine was not mRNA based and was pulled from the market because it killed so many people. The vaccines had two problems: 1. Spike protein is nasty. It causes clotting and organ damage. Doesn't matter how it gets in your body: virus, mrna, adenovirus, classical grow-it-in-eggs. 2. mRNA drugs specifically rely on special coatings which were as recently as 2017 unable to launch on the market due to toxicity that develops after multiple dosings. There's no evidence this problem was ever solved and Moderna pivoted from drugs to vaccines specifically because they couldn't solve it, the logic being that with vaccines you only have to take them once to get a lifetime of protection so the toxicity doesn't matter (doh). https://www.statnews.com/2017/01/10/moderna-trouble-mrna/ mRNA is a tricky technology. Several major pharmaceutical companies have tried and abandoned the idea, struggling to get mRNA into cells without triggering nasty side effects Three former employees and collaborators close to the process said Moderna was always toiling away on new delivery technologies in hopes of hitting on something safer than what it had. (Even Bancel has acknowledged, in an interview with Forbes, that the delivery method used in Moderna’s first vaccines “was not very good.”) nanoparticles created a daunting challenge: Dose too little, and you don’t get enough enzyme to affect the disease; dose too much, and the drug is too toxic for patients. Moderna could not make its therapy work, former employees and collaborators said. The safe dose was too weak, and repeat injections of a dose strong enough to be effective had troubling effects on the liver in animal studies. The drugs it is pushing along now, by contrast, are more modest, relying on single administrations of mRNA. |