Inactivated and live vaccines are what we consider “traditional” approaches. There are a number of COVID-19 vaccine candidates of both types, and for good reason: they’re well-established. We know how to test and manufacture them.
The downside is that they’re time-consuming to make. There’s a ton of material in each dose of a vaccine. (CDC vaccine excipients) Most of that material is biological, which means you have to grow it. That takes time, unfortunately.
That’s why I’m particularly excited by two new approaches that some of the candidates are taking: RNA and DNA vaccines. If one of these new approaches pans out, we’ll likely be able to get vaccines out to the whole world much faster. (For the sake of simplicity, I’m only going to explain RNA vaccines. DNA vaccines are similar, just with a different type of genetic material and method of administration.)
Here’s how an RNA vaccine works: rather than injecting a pathogen’s antigen into your body, you instead give the body the genetic code needed to produce that antigen itself. When the antigens appear on the outside of your cells, your immune system attacks them—and learns how to defeat future intruders in the process. You essentially turn your body into its own vaccine manufacturing unit.
Because RNA vaccines let your body do most of the work, they don’t require much material. That makes them much faster to manufacture. There’s a catch, though: we don’t know for sure yet if RNA is a viable platform for vaccines. Since COVID would be the first RNA vaccine out of the gate, we have to prove both that the platform itself works and that it creates immunity. It’s a bit like building your computer system and your first piece of software at the same time.” ~ Bill Gates