Brief post, in response to the many many many technical people that propose to print their own mRNA vaccines “now that the source is out there”.
I’ve spent a lot of time individually explaining why this is unlikely to happen any time soon, and I thought it a good idea to explain it here as well.
Mountains of details on how the vaccines are actually produced can be found on this awesome page by Jonas Neubert and Cornelia Scheitz.
First realize that a vaccine needs to have some very specific components in there. And very very very crucially, many things should also NOT be in there, not even in the minutest amounts. Because we want the vaccine to help, and not to make you ill.
So, yes, we know the mRNA sequence of the Moderna, BioNTech/Pfizer and CureVac vaccines. Moderna did not publish this sequence themselves, but because RNA can be read (‘sequenced’) in the lab, it is now also available.
As yet however, there is no technology that lets you “just print” this code as mRNA. There barely are DNA printers, and even these are not really desktop things, and from what I hear, still need you to send off your results for post-processing.
The process from DNA to nucleoside modified mRNA is not trivial. It involves vats full of bacteria and viral enzymes. In addition, the process can generate double stranded RNA which is very harmful, so that must all be filtered out again.
Then the mRNA needs to get packaged. If it is not packaged right, our cells won’t take it up. All the mRNA vaccines use very specifically designed lipid nanoparticles (LNPs). It turns out that most LNP formulations plain don’t work. You need very specific lipids, combined just right.
Then you need to get the mRNA in those LNPs. This is a very difficult and also proprietary process. I struggle to understand how that even works.
All of these steps need different forms of quality control - is the DNA code correct? Is the mRNA also the right code? Has the ‘cap’ been assembled correctly? What is the mRNA concentration so we don’t overdose? I suspect that most of the work of making a safe vaccine is actually quality control.
Finally, you need to do all this in a fully sterile environment, so as to not contaminate your vaccine. It is just as important to put the right things into the vaccine as it is to keep out anything else.
Some of these steps might well be automated and simplified in the future. One could imagine some kind of ‘Nespresso’ system with canisters with all the right reagents in there. mRNA vaccines also hold vast promise for personalised medicine, so this would be very welcome.
But for now, printing your own safe mRNA vaccine is fully out of the question. Sorry.