Episode #16 - COVID-19 - How do vaccines work?

VGS   How do vaccines work to protect us? And what are the different approaches that we are hearing about now for vaccines?  Hello and welcome to Science in 5. I’m Vismita Gupta-Smith and this is WHO’s conversations in science. Explaining this and more today is WHO’s Dr Katherine O’Brien. Welcome, Kate.

KOB   Thank you so much.

VGS   Kate, explain to me how vaccines work with our body to protect us.

KOB   Vaccines, what they do is they are a part of the germ that our body can recognize and develop an immune response to so that the next time that we see the real germ, there are already fighters in our body to protect us against the infection. For coronavirus, we know that it's a part of the outside of the coronavirus, the spike protein, is the part that if we have fighters against the spike protein, we will have a much lower chance of getting disease or getting serious disease from coronavirus. And the fighters that I'm speaking about, those are called antibodies. It's the part of our immune system that is the part that can attack that particular part of the virus.

VGS   So, we're hearing about different terms like mRNA, and different approaches. Explain that, please.

KOB   So, all of the vaccines are ultimately trying to do one thing: they’re trying to get that part of the virus, the spike protein that I just spoke about, into the body so that our immune system can develop antibodies against the spike protein. And there are two big categories of approaches to do that. The first approach is just put in the vaccine part of the spike protein or the spike protein itself. And the second category is, give the instructions for how to make the spike protein and let the body produce the spike protein. In the first group, where we actually give part of the spike protein, this is how the vaccines that we have for lots of other diseases work. And sometimes, the vaccine is developed so that it has just that part of the germ in it, in this case the spike protein. And in other cases, what is given is highly weakened or even killed version of the virus that still has the spike protein on it. So, there are different strategies within that first category of giving the spike protein. In all cases, it is so weakened the particles that are given that they don't cause disease in us. So, you're not going to get disease from the vaccines that are given even if it’s a weakened part of the of the germ. The second category, where we're giving the instructions to the body on how to make the spike protein, this is a new strategy that's being used. And it's a really important new strategy because we can develop vaccines very quickly, a much more efficient way of developing vaccines and using the body's own ability to produce proteins is a really powerful tool.

VGS   Kate, when we hear about vaccines developed from parts of viruses, people may have questions about safety. Speak to us about safety of these vaccines.

KOB   Our immune systems are incredibly powerful. On a daily basis, a weekly basis, a monthly basis, our immune systems are seeing all kinds of viruses that come at us in our noses, in our mouths, in our intestinal track on our hands. What's out there and readying itself for when it's exposed to something that could be causing disease. What the vaccines do is they provide to the immune system a small part of a germ that we know can cause disease. And it's training the immune system so that it is completely ready when it actually sees that particular germ. The vaccines that we have that have been used in hundreds of billions of doses for decades, and in fact for centuries for some of the vaccines, have been studied, evaluated for safety and for the impact that they have. And, we have a safety system for all vaccines that is constantly looking at the information about the performance of the vaccines and picking up any issue around safety that might arise in the future. So, I think we can be really well assured that we have a very strong system in place to both look at safety, assure safety, before a vaccine is authorized for use and will continue to monitor safety even after it is deployed for widespread use.

VGS   There you have it, Dr. Katherine O'Brien explaining how vaccines protect us. Remember there is a lot of misinformation about vaccines out there. So, please share this information with your loved ones, with your friends and your networks, and be the source of scientific, evidence-based information. Until next time then. Stay safe, stay healthy and stick with science.