Pfizer (NYSE:PFE) and its German partner BioNTech (NASDAQ:BNTX) reported incredible efficacy data from a phase 3 trial for their mRNA coronavirus vaccine candidate. This news, paired with the equally impressive data from Moderna (NASDAQ:MRNA) about its candidate that takes a similar approach, inspired much hope around the world and injected optimism into the stock market.

The Motley Fool sat down with Dr. Jeremy Brown, author of Influenza: The Hundred-Year Hunt To Cure The Deadliest Disease In History and Director of Emergency Care Research at the National Institutes of Health. Dr. Brown shared what investors should know about what the proof of efficacy for mRNA vaccines means.


Corinne Cardina: Dr. Brown, is there anything you can tell us about how this is different from the traditional vaccine approach that we see with like a flu vaccine?

Dr. Jeremy Brown: Sure. In the traditional approaches, what people do is they grow the virus and grow it in such a way that it is inactivated. There are different clever ways of doing this, but basically, you have what we could call a dead virus. Although, of course it's a question whether viruses are living in the first place, but let's assume that it's a living thing and it's killed. But its body is still there that is presented to the our body, to our immune system. The immune system learns what the virus is and so it's primed and ready should that virus return. That's what happens with influenza. A little bit more complicated with influenza though, because each year, there are several different strengths of influenza that are especially dangerous or especially likely to cause disease. We get the influenza vaccine, which contains three or sometimes four different subtypes of the influenza virus. Now with these other vaccines that we're now seeing from Pfizer, Moderna, others, they are using genetic engineering in a wonderfully clever way. Taking a small part of the messenger RNA and amplifying it in such a way that the human body learns to understand it. Then is primed in a way to that bit of the vaccine, if you like not to the whole vaccine, but that bit. That bit is enough of course, to allow our bodies to mount an immune response and fight the vaccine off should we become reinfected. It's the next version of vaccine development. Vaccines go back to the time of Louis Pasteur and Edward Jenner in the 1700s, smallpox and so on. But nobody has had the tools that we have to allow us to bypass many of the steps and go directly to building a vaccine based on the genetic makeup of the virus itself.

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