 You're watching News Made Easy. I'm Anindya Chakravarty. This is our new show where I'm going to take one big story every week and try and make it as simple as possible so that everyone can understand it. Because all of us need some information, some credible information about everything that matters to us. That's the only way democracies can work. In fact, I'm going to try and make it as simple as possible for even a fifth grade student to be able to understand it. Because after all, citizens need to know whether they're young or old. So we're going to kick off the first episode by focusing on something that all of us have been wondering about, all of us have been worried about. And that's the coronavirus vaccine. Keep watching. So as you know, India has approved two vaccines against the coronavirus. One is developed jointly by Oxford University and AstraZeneca. And it's being produced in India by Serum Institute. And it's called Covishield. And the other, somewhat controversial, is Bharat Biotech. That's called Covaxine. It's being developed not just by Bharat Biotech, but also by the Indian Council of Medical Research. Now to understand how these vaccines work, we have to first understand how our bodies get infected by viruses and bacteria. Think of our body as a city with many buildings, some are houses, and others are factories and offices which keep the city running. This city is always under attack from invaders who want to take over the buildings, use the food inside to live and multiply. We can't see these invaders because they're super small, a vast number of viruses and bacteria and other parasites which are always around us. Once they pass through the borders of our body and enter the bloodstream, they can quickly enter our cells, use what's inside to replicate and create more copies of their cells. These copies then break out of the cells and flow through the blood, looking for more cells to infect. And the part of our body that's under attack stops working in the way it should. Luckily, our bodies have an inbuilt defense mechanism which helps us fight viruses when they enter us. And one of the first lines of defense that the body has is, you got it right, snot, runny nose, a blocked nose and a wet cough, which doctors call productive cough. The snot in our nose makes it tough for these intruders to get through our nose lining and the runny nose or an occasional sneeze pushes them out of the body. The second immune reaction is fever, which does two things. It slows down the viruses and bacteria from spreading because they don't work well at higher body temperatures. Also, fever is a signal to our immune system that something is wrong and it has to start working. That's when special soldier cells in our body begin their counter attack. The cells create specific antibodies to target the invading bacteria or virus, disarming them and even killing them. Our body stores these antibodies and our immune cells also remember what these viruses and bacteria look like so that when they come and attack us again, the immune system can quickly counter attack and expel them from our body and stop damage. Now, the problem here is that more often than not, you need to be infected at least once by a virus to become immune to it. But something like COVID-19, you don't want to be exposed to it. You want to already have the immunity before you can be exposed or infected by the coronavirus. Now that is where vaccines come in and how do vaccines work? They try and look at ways to disarm. Disarm the virus or the bacteria. In the case of SARS-CoV-2, the COVID-19 virus, vaccines target their spike proteins. These are the tulip-shaped spikes that cover the surface of the virus. They look for proteins on the surface of our cells inside our body that they can latch onto and then enter through the cell membrane. So if these spike proteins can somehow be disarmed or blocked, then it is possible to stop the coronavirus from replicating inside our bodies. That is exactly what the coronavirus vaccines also try to do, including the two vaccines which have been cleared in in-depth. They basically insert the coronavirus' spikes in certain different ways into our body but in an harmless fashion. They cannot replicate, but they could still present the spikes for the body's immune system to recognize them and the immune system to kick off. A special type of soldier cell called antigen presenting cell picks up these spikes, digests them and then pushes out fragments of these spikes on its surface. Another type of immune cell called helper T-cells recognize these spikes and trigger an alarm calling immune cells to come to the infected region and fight the coronavirus. There's another type of soldier cell called B-cells. To understand what they do, imagine a tray full of Lego pieces with different shapes. B-cells have hundreds of types of proteins of different shapes that can lock onto intruding proteins and pull them into themselves. In the case of the coronavirus, the B-cells take in the spike fragments and again push them out on their surface. If a helper T-cell bumps into these spikes, it can trigger the B-cell to pour out protective proteins known as antibodies that exactly match the coronavirus spikes. These antibodies quickly lock onto invading coronaviruses and stop them from entering other cells in our body. Not every T-cell is a helper. Some are killers. These killer T-cells can seek out any cell that displays coronavirus spike proteins on its surface and destroy them. So the vaccines create killer T-cells and antibodies in our body even before a coronavirus infection can take place. So that means if we're ever exposed to coronavirus, the chances are that it will not be able to do much harm to us and we'll be able to fight it off pretty quickly. Right now, no one knows how long these vaccines will work. That is why they come in two doses. The first to begin the process of making antibodies to fight the coronavirus and the second booster shot to make the immunity even stronger and hopefully last longer. Some scientists believe that the immunity created by the vaccines may last even after the killer T-cells and antibody levels in our bodies drop. That's because of another type of immune cell called memory B-cells and another called memory T-cells which could retain information about the coronavirus for years, even decades. Now, normally vaccines take years to develop. They have to go through various stages of trials for many months, many years over many people and only then do they get clearance to be administered to the wider population. But the times of coronavirus are very different. This is a completely different animal. The pandemic has shut down everything. It has made us wear masks any time we go out in public and stay away from each other. We mostly locked inside our homes without meeting our friends and larger family. It has stopped us from travelling and it has literally broken our economies. That is why every vaccine across the world has been approved on an emergency basis this time. It did just a few months of tests on real volunteers. Now, if you look at India, we've gone one step ahead. Bharat Biotech's co-vaccine has been given clearance even before its third phase has been completed. The third phase, which is needed to find out whether it's effective or not. Even its second phase, which tells us whether the vaccine is safe for humans or not, hasn't been fully processed. The data is still to be fully processed but it has been given emergency clearance and that has worried many scientists and doctors which has made them a bit nervous. The government says that the Bharat Biotech vaccine will be given only to those who are willing to take it or willing to participate in the trial. So it's in a trial mode. There are questions even about the vaccine being produced by AstraZeneca and Oxford in India by Syram Institute because it's still not clear from the data what dosage is optimal. Is it two doses or one and a half doses? So there is some confusion there as well but the bottom line as of now is that most doctors, most scientists agree that it's better to get the vaccine right now, two shots even if it has some small, minor side effects here and there than be infected by the coronavirus and get COVID-19 which can have long-term impact on your health. That's our first episode. We'll see you next week again.