Proteins are chemical compositions - useful machines. Each one (especially outside the context of a cell) requires custom environments to be kept stable. And the processes to manufacture them require other organisms - from which you must now purify that (unstable) protein. And it’s not self-replicating so if you need weekly doses of Ng of material for X doses, you need to produce that much material. RNA solves all of these issues. RNA is a template of common composition that can encode any protein (same chemistry, but in different orders can encode for any arbitrary protein). It can be synthesized in a chemically defined system. And it can persist long enough to produce many generations of proteins. And it can even sometimes be designed to be self replicating. From a theoretical perspective it’s so much better than delivering a custom-purified shot to your blooodstream - different for each virus.
The second question is the hard part - delivery. With the advent of ‘gene therapies’ we needed easy to deliver DNA and RNA to living human cells. We’ve come a long way here and have a number of technologies (oftentimes co-opted from viruses) that range from permanent integration into the cell’s genome (lentivirus) to transient (AAV [see Oxford’s vaccine]) to chemical transfection (Pfizer and Moderna). The RNA in these vaccines is chemically more stable than normal RNA, so it will have half-lives of weeks rather than hours inside cells - but it will degrade after a time and the cells will no longer produce the protein. Proteins in a cell have half-lives of hours to days and even stabilized RNA will be less than a month. After that the material produced by this 'vaccine' will be degraded and gone. However, at that point, the immune system will have permenantly 'encoded' antibodies for the shape of the produced spike protein.
What changes are made to mRNA in these vaccines to make them last longer? Also wouldn't our immune system attack it as foreign then? It seems to me as a layperson that this must have been a key novel and clever part to make these vaccines work. I'd like to read more but don't know where to start.
Proteins are chemical compositions - useful machines. Each one (especially outside the context of a cell) requires custom environments to be kept stable. And the processes to manufacture them require other organisms - from which you must now purify that (unstable) protein. And it’s not self-replicating so if you need weekly doses of Ng of material for X doses, you need to produce that much material. RNA solves all of these issues. RNA is a template of common composition that can encode any protein (same chemistry, but in different orders can encode for any arbitrary protein). It can be synthesized in a chemically defined system. And it can persist long enough to produce many generations of proteins. And it can even sometimes be designed to be self replicating. From a theoretical perspective it’s so much better than delivering a custom-purified shot to your blooodstream - different for each virus.
The second question is the hard part - delivery. With the advent of ‘gene therapies’ we needed easy to deliver DNA and RNA to living human cells. We’ve come a long way here and have a number of technologies (oftentimes co-opted from viruses) that range from permanent integration into the cell’s genome (lentivirus) to transient (AAV [see Oxford’s vaccine]) to chemical transfection (Pfizer and Moderna). The RNA in these vaccines is chemically more stable than normal RNA, so it will have half-lives of weeks rather than hours inside cells - but it will degrade after a time and the cells will no longer produce the protein. Proteins in a cell have half-lives of hours to days and even stabilized RNA will be less than a month. After that the material produced by this 'vaccine' will be degraded and gone. However, at that point, the immune system will have permenantly 'encoded' antibodies for the shape of the produced spike protein.