The short answer is that proteins are too complex to manufacture, and it’s more effective to instruct your body (which has a lot of protein manufacturing capaci

The short answer is that proteins are too complex to manufacture, and it’s more effective to instruct your body (which has a lot of protein manufacturing capacity) to produce the protein. There are attempts to use peptides. They are much shorter chains of amino acids , they are easy to produce, but it’s difficult to find peptides that reproduce the external structure of the virus. There is an experimental Russian vaccine based on peptides, but the results haven’t been published yet.