To add dang (and for others), for future reference: in regulatory affairs, “cleared”, “approved”, “granted”, and “authorized” are distinct actions for the FDA. These verbs are not interchangeable and using the wrong word can bring significant (financial, for the associated company) consequences because it implies that the FDA did something they did not, e.g., cleared for a 510(k) device vs granted for a de novo device.
I really don't know a single thing about vaccines or biology really. That being said, I am curious - are there are trade offs to be made with this mRNA technique? It sounds like mostly upsides, but perhaps there are considerations for this approach over a traditional one?
The major trade off is requiring low temperatures to transport and store. Pfizer currently requires -70C and Moderna -20C, whereas other vaccines only require fridge temperatures or even room temperature! The vaccines like the viral vector and mRNA vaccines that target specific viral proteins also may miss out on antibodies for other viral proteins that a live attenuated or deactivated vaccine may produce.
> ...may miss out on antibodies for other viral proteins...
Do you mean to say that a more traditional one which uses the deactivated virus can help find proteins related to the virus but not specifically targeted, or do you mean that a traditional one could target other proteins that could apply to _other_ viruses?
Not the OP, but - if I'm reading this right, the mRNA vaccine contains the code for one specific (or a small subset of) viral protein, which is what the immune system is induced to target. In a traditional vaccine, the immune system is exposed to the entire viral protein coat, and therefore may learn to target multiple different proteins from the same virus, not just the spike protein. I suspect OP's suggestion is that it's possible providing the entire virus may provide additional or more robust immunities against the same virus that we don't get from the more targetted mRNA vaccine.
I'd be getting very outside my lane to speculate on whether inducing immunity against multiple proteins would potentially apply to other viruses also carrying those same proteins - I don't know how specific or how contextual the immune system's response is in this case.
Another big difference is cost. Pfizer's looks like it is going to be $20 per dose in the US. Moderna's is going to be $15 per dose in the US and more after the initial 100 million dose deal with the government is over. Moderna has said they expect it to be $32-37 retail.
The leading conventional vaccine, the one from AstrZeneca, will be under $4 per dose in the US for the 300 million doses they have agreed to supply to the government, and they have said that they will "in perpetuity" supply it at cost to low and middle income countries.
That will probably make it or another conventional vaccine be the one that makes the biggest difference globally for this pandemic.
Cost is a significant difference but I’d be interested to understand why the costs vary so much. For instance, if the cost difference is mainly because of the cost of cold storage and transport then it’s really only the one “trade off” but it is probably more complicated.
Also, the Oxford/Astra Zeneca vaccine isn’t a conventional vaccine but a viral vector vaccine which also has never been approved for use in humans. It acts similarly to the mRNA vaccines but uses a hollowed out adenovirus sheath as the transport mechanism of the RNA into the cell.
Cost for now is because the tech is new. Long term manufacturing cost benefits mRNA, because essentially you use the same "hardware" for each vaccine just different "software". They can comparatively much more easily produce something like RSV vaccines or anything else with the same core assembly line.
Here's a longer 43 minute video explaining them and the Moderna/Pfizer/BioNTech/Astrazeneca clinical trial processes in more detail. The biochem part starts at 12:30.
> Bell’s palsy was reported by four vaccine participants and none in the placebo group. These cases occurred at 3, 9, 37, and 48 days after vaccination. One case (onset at 3 days postvaccination) was reported as resolved with sequelae within three days after onset, and the other three were reported as continuing or resolving as of the November 14, 2020 data cut-off with ongoing durations of 10, 15, and 21 days, respectively. The observed frequency of reported Bell’s palsy in the vaccine group is consistent with the expected background rate in the general population, and there is no clear basis upon which to conclude a causal relationship at this time, but FDA will recommend surveillance for cases of Bell’s palsy with deployment of the vaccine into larger populations.
[0] https://www.reuters.com/article/us-health-coronavirus-pfizer...