I just heard a blurb on our local NPR affiliate that a local doctor’s office is recruiting volunteers for a clinical trial of a “plant-based” COVID vaccine. This same office was a local partner for the Moderna clinical trial, and I have some professional familiarity with this office and I’ve never seen any prior indication of alt-med or woo tendencies from them. But this blurb seemed to be pitching “plant-based” as an advantage over existing vaccines. They didn’t literally say “all natural”, but that seemed to be the implicit pitch.
So, any idea what a “plant-based” COVID vaccine would be? Is this a legitimate thing (there certainly have been real medicines derived from plants) or alt-med “all natural” woo?
The top google search is Nature magazine, but if you read carefully at the top it’s actually an ad
The company is called Medicago, though it seems there may be others looking at similar techniques. From a quick skim it seems they are using plants rather than chicken eggs in the production process, not that the plants themselves have any sort of antiviral properties.
No eggs or any other animal tissue are used in the production process for nucleic acid vaccines. So I have no idea what “plant-based” could mean with respect to the mRNA (Pfizer, Moderna) or DNA (J&J, Astrazeneca) vaccines.
It is likely that mice were used as some stage of research and development. Their immune system closely resembles humans in most general respects. And cell culture using animal-derived cell lines was certainly used. Here it’s important to note that imflammatory language like “use of fetal tissue” is highly misleading, sounding as though fetuses are being mashed up constantly for research or something ridiculous. What it means is that a few cells were extracted from ONE aborted fetus decades ago, and used to generate an immortal cell line that has been maintained since then in cell culture passage, an entirely in vitro process. Other immortal cell lines derive from other sources, but all were historically sourced from some kind of human tissue. You can’t do any kind of useful research in this field without using cell culture.
So from a research and development perspective, I can’t imagine what “plant-based” would mean. And from the production perspective, the new nucleic acid vaccine technology already allows us to produce vaccines entirely in vitro without any animal tissue.
It’s part of the production, not research and development:
The production approach of a plant-based vaccine involves cloning the vaccine candidate into a plant expression system, which is capable of promoting the expression of the candidate gene in the plant, which then produces the antigenic or protective protein.
I appreciate that there are plant-based systems for manufacturing proteins. But none of the major COVID vaccines are proteins. They are nucleic acids. No animal (or plant) tissue is used in synthesizing nucleic acids. I assume that the objective is to not use animal tissue. We already do that. If the objective is to add plant tissue, you can eat a salad with your vaccine.
I guess there might be some peripheral aspect to how ingredients other than the primary nucleic acid component are manufactured.
I just realized that I slightly misstated the situation for the production of nucleic acid vaccines. Cell culture would be used in R&D for all vaccines. Cell culture would not be used in the production phase for mRNA vaccines, but it would be used for the production of adenovirus DNA vaccines.
Yes, but this is for clinical trials for a new vaccine, not one of the existing major vaccines.
I think @tofor gave a plausible answer: the clinical trial is for a new, protein-based vaccine, which is using plants as a bio-reactor. That would certainly match the tenor of the blurb, which seemed to be aimed at recruiting people who are hesitant about the current vaccines.
But surely the point (if any) of using plant tissue is to avoid using animal tissue. And the existing major vaccines already don’t use animal tissue in production.
As I said, if the objective is to introduce plant tissue for its own sake, you can take one of the mRNA vaccines and eat a salad.
Shrug. It’s not my vaccine. It’s just a blurb I heard on the radio.
But, and I Am Not A Vaccine Researcher, my understanding is that plants are already used as bio-reactors for some materials, and there are potentially significant logistical advantages to producing vaccines using plants as bio-reactors. I suspect the emphasis on “plant-based” in the short recruitment blurb was, as I said, intended to reach vaccine-hesitant people. There was nothing in the blurb about not using animal components, just that this was different than the current vaccines in use because it was “plant-based.”
Then why emphasize plants front and center? The far more significant differentiating aspect would be that any proposed vaccine using this technique would consist of synthetically produced protein, rather than nucleic acid or virus. It would not be of greatest primary significance how the protein were manufactured, or efficiency and scalability of production. The first question would be to demonstrate the efficacy of a protein vaccine relative to other types.
None of the ones used in the US are, but IIRC, one of the vaccines used in Russia is a partial-protein vaccine. IIRC.
And as the OP said, there’s nothing preventing a new vaccine from being a protein, or partial-protein.
Because people are stupid.
There are people refusing the vaccine because some poor baby was aborted back in 1960 to create the vaccine (in spite of the fact that Roman Catholic authorities issued a decision on this a couple of decades age, which amounted to “what’s done in done; now let’s save lives”).
Then, there are probably vegans refusing the vaccine if they think it was cultured in eggs, or mice, or whatever, at some point, even if it was the boyfriend of the cashier at the co-op who told them so, because he read it on a website.
It was a just a brief radio blurb from a local doctor’s office that’s participating in the trials trying to recruit people who haven’t already been vaccinated. They’ve got to give them some reason to sign up for this trial rather than just get one of the ones that’s already been tested and approved.
I’m personally satisfied that @tofor has provided a reasonable explanation for what I heard.
Sure, but your question was whether it’s a “legitimate thing”. Expounding the fact that we have plant-based protein expression systems is not relevant in the COVID context until somebody has demonstrated a protein vaccine with efficacy comparable to the existing vaccines. And any appeal to people who for misguided ethical reasons want to avoid cell culture is bogus. The same tools would be required for the R&D.
All indications are that it’s a legitimate vaccine produced by a legitimate company. Real vaccines are being produced using plants. It’s not some sort of holipathic quackery. The OP need not lose faith in the doctor participating in this trial.
Whether this is somehow better than other vaccine tech remains to be seen. The company producing the vaccine clearly thinks so, but ymmv.
Since I explained exactly why I think it’s not a “legitimate thing” in the current COVID context, I object to you snipping that part of my quote and substituting your straw man. I did not claim that plant-based protein expression systems are quackery.
But what trial, for what vaccine? Have I overlooked a link? OP mentions a clinical trial, but I haven’t seen anything in this thread substantiating that and explaining what this trial is doing. A clinical trial to demonstrate the efficacy of a protein vaccine is indeed the first step here. Whether on not that protein is produced in plant expression systems is not the principal question.
I don’t know what to tell you. I heard a blurb on the radio from a local doctor to recruit volunteers for a clinical trial. I don’t know how to “link” to that or “substantiate” it. I guess the doctor could be lying about a clinical trial, or I could be lying about hearing the blurb, but…shrug.
I asked if a “plant-based vaccine” was a legitimate thing or woo. @tofor seems to have answered that - it’s a real thing, it’s just using plants as bio-reactors to produce a protein for a protein-based vaccine.
The fact that the local doctor recruiting volunteers chose to emphasize “plant-based” does seem to be woo-friendly if not actual woo, but the basic idea of the vaccine itself seems legitimate, which is all I was asking.
So to answer my own question, googling finds this for example:
And, as I suspected, one motivation does appear to be “ethical concerns” about the use of cell culture, concerns that I think are bogus.
What would be great about a protein vaccine would be that it if it worked as well, it would likely be far more stable than mRNA, and the “lower” tech could probably be scaled up more readily, whether through plant-based or other expression systems. It could be a boon for vaccinating large numbers of people without First World infrastructure.
Medicago’s [COVID-19] vaccine candidate is currently in Phase 3 clinical trials. The Phase 1 results have been published on November 10th, 2020 by a press release. Based on these results, we received the agreement of regulatory authorities to launch Phase 2/3 clinical trials on November 12th, 2020.
Of course, I have no way of knowing if this is the particular trial is the one @gdave heard an ad for.