Nearly 2.5 billion of us have been reintroduced to the process of getting vaccinated recently, and if the experience has taught us two things, it’s this: firstly, that vaccines are a medical miracle capable of saving millions of lives, and secondly, that they’re no fun at all to get.
They hurt when they go in. They hurt for days afterward. Your arm gets all red and itchy, and worst of all, you can’t even complain about it because it makes you look like a little baby who doesn’t want to get their shot. There must be a better way.
But what if getting vaccinated was as simple as eating a bowl of cornflakes? A perspective published today in Science makes the case that future vaccines may not come to us through a needle, but from the greenhouse – the pharmaceutical preventatives will be grown inside plants.
“The use of plants for the production of therapeutic proteins, called molecular farming, was proposed as an alternative biomanufacturing method in 1986,” explain the authors. “[Recent] successes have revived interest in plant-produced pharmaceuticals for human use, which could include edible drugs.”
It's not as bizarre as it sounds – in fact, there are already medications out there that have been developed like this. In 2012, the FDA approved a treatment for the rare Gaucher’s disease that was cultured in carrot root cells, and various enzymes and proteins have been available for decades that were grown in tobacco, rice, maize, and other plants. Vaccines may not be out there just yet, but they’re not far off: a plant-grown flu vaccine has recently shown promise in phase 3 clinical trials, and researchers are already on the lookout for ways to develop vaccines for HIV, Ebola, and even COVID-19 using plants.
Plus, the authors point out, molecular farming has a lot of benefits over traditional methods of vaccine production. It’s cheaper, since most of the things you need to grow plants can pretty much be found lying around for free outside – “greenhouses,” they point out, are “cheaper than bioreactor suites.”
It’s also fast – the authors note that new vaccine candidates can be obtained in as little as three weeks, which is a huge advantage against new or emerging diseases – and safer since plants can’t be contaminated by animal pathogens. Much like with food production, plants are also better for the environment, since they’re much less resource-intensive and even produce more vaccine by weight than traditional methods.
On top of that, plant-based vaccines can actually be more effective than their traditional counterparts. The different internal structure of plants means that they provoke a stronger immune response, and their cells contain naturally occurring particles which can make that effect even more potent. With standard vaccines, these particles, known as adjuvants, often have to be added separately – and they can give you more side effects as a result.
So far, the growing range of plant-made vaccines have mostly been administered the same way as a normal vaccine: as a shot. But there’s another option the authors want us to consider: what if we just … ate them?
“Oral administration of drugs is a user-friendly alternative to the intravenous route,” they write. “[It] can mitigate the adverse events associated with intravenous administration of pharmaceuticals. Gut immune responses are crucial for tolerance to food and self-antigens and play an important role in ensuring a balanced immune system.”
Not only that, but edible vaccines might be even cheaper and easier to produce, since they wouldn’t need to be clinically processed and purified as much before being ready to administer. What’s more, they could be dehydrated and stored at room temperature until needed – an advantage that is especially potent after certain recent world-wide events.
There’s just one problem: so far, edible vaccines simply haven’t proven themselves that effective. A slew of potential candidates were trialed back at the turn of the century, but none prompted an immune response better than vaccines delivered via the standard routes.
As a result, the idea of edible vaccines was seen as something of a non-starter for some time. But now, the amount of vaccine proteins that plants can produce has been “increased substantially”, the authors say, meaning that modern edible vaccines may be capable of producing “meaningful immune responses”.
Of course, that doesn’t mean edible vaccines are right around the corner – a lot more research will be needed before they’re definitively a worthwhile and safe option. Since it’s such a new area of research, there’s also a lot of infrastructural and legal intricacies that will need to be untangled as the science develops.
But should the authors’ hopes bear fruit, we might be facing a future where we’re kept healthy not with vaccines, but snack-cines. And if only for that single pun, that sounds like a bright future indeed.