The reality of corona vaccine | कोरोना वैक्सीन की वास्तविकता
Introduction of the article
We're going to talk about covid-19 vaccine. We're going to primarily talk about four vaccines that are being funded by operational work speed. We're going to talk about AstraZeneca or the Oxford vaccine, Moderna, Pfizer biotech and Covaxin.
We are talking about how these vaccines are being developed. What are the phases and stages they have to go through then we'll talk about the mechanism of action how these vaccines actually work in the body. And then finally we'll go over some of the intera more press release data that have been released by the company's about these vaccines.
So what we have to do is first have a complete understanding of what the goals of vaccine development is so throughout all of these stages.
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| The reality of corona vaccine |
Goals of vaccine
There's two primary goals that we're trying to meet by developing these.
Exceeds the first goal that is going to be set forth is safety. That is the utmost priority for a vaccine being developed. In other words. We want to make sure that any side effects that these patients are trials that are being tested any of the patients that are actually being tested with this vaccine aren't developing any serious or deadly side effects related to the vaccine. The other goal is efficacy and this is what we have to expand on a little bit more because this is what's talked about a lot right now in the media. So efficacy can be law thought of in two ways. It's basically the efficacy of the vaccine to prevent disease okay, or the efficacy of the vaccine to prevent infection that is two distinctions that we truly have to understand.
Phases in developing a vaccine
Well, there's a couple different face. We're going to kind of list them out. So you have them and we're going to discuss what they do in those phases.
Preclinical phase:
The first one is your preclinical phase and this is primarily where you do animal testing. This is animal testing after that if animal testing is pro basically safe and effective you move on to the human trials.
Clinical phase :
We're here consists of three phases.
Phase 1: here you're taking on human trials, but it's a small population size.
Phase 2: if phase 1 still effective and safe, then you're going to be going on to phase two. It's just a little bit of a larger sample size after that if again still safe and effective or moving on to the next phase.
Phase 3: This is just a larger human population.The last thing that you're testing here is dosage.
I mean by those are trying to figure out the upper limit of the dose and you're trying to find the lower limit of the dose.
Last phase: In sample size that you're testing finally if it's met all the safety and effective goals that it had planned out for that vaccine it then is sent for FDA approval.
Working of different vaccines
I want to tell about is how these vaccines produce an immune response.How do we develop antibodies against this virus?
Moderna and Pfizer:
Then they're using the lipid nano-particle with the MRNA and obviously you'll get an injection. It would release the MRNA into the cell now. Once the MRNA is in this host cell.It does not get involved with our nucleus, it doesn't get it incorporated into the DNA. mRNA actually uses our cells ribosomes and when a uses the cells ribosomes are the rough endoplasmic. It is going to be making proteins and the formation of protein by mRNA is known as translation. From this process cell is going to form to types of protein. One of them is MHC2. And this is only found on what's called antigen presenting cells.
The MHC 2 complex is only found on a couple cells B cells which are your lymphocytes, your macrophages and dendrite cells . these are really the only cells that have these MHC2 complexes now when they express these basically these protein the S protein shape on the actual complexes. What does it do? Well the tracks in immune system cells like T helper cells. S protein interacts with the viral antigen and it has another protein which interacts with the MHC 2 complex and that is called a CD or protein. Once this interaction occurs between these two things that T Cell becomes activated and it starts to release cytokines and there's a ton of these cytokines that they release interleukin.these interleukin s do a couple things. They tell a particular cell in your body very important cells, especially with regards to what we're talking about here called a B cell, to proliferate. When they proliferate they differentiate into these very Special cells called plasma cells and these plasma cells once they're developed and stimulated due to these different cytokines being released. They start to make antibodies and guess what these antibodies. These antibody bind onto that protein on the virus, we could neutralize the virus or enhance the destruction of the virus.
Second protien is called MHC1 proteins now MHC1 proteins are found on all nuclei.
So that's kind of how this moderna and Pfizer biotech vaccine is actually helping us to generate an immune response.
AstraZeneca Oxford Vaccine:
This one is not mRNA technology this actually has something really interesting. It contain nucleic acid inside of it is called a chimpanzee Adenovirus.
Inside of the Chimpanzee Adenovirus is a DNA molecule. The DNA molecule and have the same kind of process of working here.
When you inject vaccine, DNA again latch on to this host cell when it latches on to the hosts a little release the DNA into the host cell right into the cytoplasm. DNA migrate, into the nucleus, once it is in that nucleus. It does not get incorporated into the DNA from what AstraZeneca says, they say that they use the host cells enzymes to convert the DNA into mRNA then they take the mRNA that's generated here and put it out into the cytoplasm. Where it will then interact with the host cells ribosomes then get translated and make proteins and these proteins will then do what they'll get expressed on the cell membrane and you guys already know what happens here.
We talked about how the vaccine works right how it generates in a an antibody response or an immunologic response.
Covaxin:
Covaxin was developed by Bharat BioTech. They developed their vaccine by very different way than all of others. They manufacture covaxin by inactive corona virus, means that the covaxin contain dead virus. When this vaccine injected in human body then it promotes the immune system to produce antibodies against the corona virus.
Calculating the efficacy of different vaccines
Moderna : They started off with about a sample size of around 30,000 participants. These 30,000 participants you break it up into two groups. One is placebo, They're not really getting the vaccine and other is Vaccine group, They're the ones that are getting the moderna vaccine. Well after they carried out this study and they had them come back if they had symptoms. The ones who were in the placebo group about a 185 people tested positive for covid-19. But in the vaccine group only 11 people tested positive. It is a very big difference.
We take out of a 185 Placebo and 11 vaccine you would take 185 -11 right and you would get somewhere around 174 over 185 multiply that by a 100 you're going to Around 94.5% efficacy against the disease that's amazing.
Efficacy = (185 - 11/ 185) * 100
Efficacy = 94%
Storage temperature = -20 degree Celsius
AstraZeneca Oxford vaccine : They do a different thing that they done their study in two different regions one is Brazil and take 9000 volunteers and other is UK and take 3000 volunteers and break up participants into two groups one is placebo and other is vaccine group and they do same as in moderna. By this experiment they got efficacy about 70% .
Covaxin : The Bharat BioTech done their trial on 25,000 volunteers by dividing them into 2 groups in placebo and vaccine group, and they found the efficacy is about 81%.
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