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Vaccines: A brief Introduction

By Shivam Panda

In 1796, the first vaccine was created by Edward Jenner. He injected a small dosage of the cowpox virus into a young boy and later proved the boy’s immunity to smallpox (a family of the cowpox virus). Today, pharmaceutical companies all around the world labour day and night to produce a usable virus to combat the ongoing coronavirus pandemic.  Since then, the production of vaccines have been made a thriving occupation and has evolved into a meticulous process to ensure the survival of the ever-growing population of mankind. Before getting into the testing and approval of these vaccines we must first talk about the different type of vaccines. 


1) Live Attenuated Vaccines:

These vaccines (like those for Measles, Mumps and Rubella) employ the introduction of weakened or asymptomatic viruses into the bloodstream so as to trigger the bodies immune response towards the specific proteins on the virus, hence effectively immunizing the subject. These vaccines are quite effective, but still cannot be used on those with already compromised immune systems. As a result, they are generally used as precautionary vaccines.


2) Inactive Vaccines:

These vaccines (like those for treatment of polio or Hepatitis-A) employ the introduction of dead cells of the virus into the bloodstream so as to sensitize the body’s immune system to the virus’s protein ‘print’. Since these are dead cells the trigger response of the immune system is not as vigorous and hence the may require booster shots. However, they can be introduced into already compromised immune systems. 


3) Subunit Vaccines: 

These vaccines usually consist of certain characteristic proteins/ carbohydrates of the virus so as to sensitize the subject to that family of viruses by triggering an immune response. They work more or less like the previously stated ‘Live Attenuated Vaccines’. There are some experimental DNA vaccines but perhaps the most relevant vaccine of such type is the mRNA vaccine. The pharmaceutical company Moderna, Inc. has produced the vaccine ‘mRNA-1273’ that is currently under testing and has enlisted 45 healthy adults for the same. What's so groundbreaking about this vaccine is that it completely skipped the phase 1 testing and has moved onto phase 2. 

They were able to accomplish this because they aren't actually endangering the subjects by introducing specimens into the bloodstream as a conventional vaccine is developed. Essentially, what they are doing is introducing a genetic sequence that codes for the tiny protein spikes on the SARS-Cov virus (the virus responsible for coronavirus). The premise is that the body will consequentially produce the protein that bonds with human cells and in response trigger an immune response, therefore preparing the body for when the actual virus infects the system. Think of it as a practice test before the test day.  They were able to do this thanks to the Chinese scientists who successfully sequenced the virus back in January this year. That information was made public so as to give companies a head start on the process.



The journey from developing to manufacturing vaccines:

To date, there are 47 prospective coronavirus vaccines in various phases of production trials around the world. It’s a meticulous process, bringing the vaccines to the masses. Before human trials a vaccine is tested on lower level organisms like mice, then non-human primates then finally on humans. Even the human trials are divided into phases:

  • Phase I:

The first phase is extremely experimental and basically, tests for safety. It strives to make sure there are no negative/ adverse effects. 

  • Phase II:

The second phase tests for efficacy. This means the testing of efficiency and effectiveness in relatively larger masses. This kind of testing is usually conducted among a few hundred people and in places where the virus whose vaccine is being produced has already taken over. This process is one of the more laborious of the phases. In this phase there are control groups compared with experiment groups and surveys are taken to keep track of spread, unprecedented adversities such as side effects and even the assessment of how effective the vaccine in practical scenarios

  • Phase III:

This phase is the introduction into large communities of a subject count of around 10,00-40,000 people. It's more of a last precaution and usually tests for the feasibility of the vaccine.

After all, this comes the approval license, the actual manufacturing and distribution of the vaccine. It usually takes half a decade for the actual commercial production of a vaccine. While optimists predict the first distribution of vaccines in 6 -8 months conventional predictions estimate a timeline of approximately 2 years. So while the situation seems grim right now, it is only the beginning of a long battle. 

The bane of this pandemic is not marked by the production of these vaccines, but rather the distribution. Even after a year at best, once the vaccine is ready for manufacture, a plethora of quite concerning factors stand in the way of us winning this battle against the pandemic. There is an ethical and moral conundrum for the distribution of the vaccine, “ Should wealthier countries win the bid for the bulk of vaccine productions, or should it be distributed on the basic population to support the less wealthy countries?” if the vaccine were to be first manufactured by private companies like Moderna, then they’ll have private interests. Even after distribution which part of the population should be prioritized, healthcare workers? Senior citizens? The teaching and education segment of society?

Even after the production of these vaccines who knows which countries will accept them or not. National agencies like the FDA (Food and Drug Agency) and CDCSO might feel that the vaccine is reliable based on the results of testing and hence those countries may not be privy to immunization against the vaccine.



Rational thought suggests that it is a long, long time before we go back to ‘normal’ (normal in quotes because this life is the new normal). It is an incredibly complicated path to normality, and all around the world scientists strive to help those who have succumbed to the virus. So, while there may be the talk of vaccines and immunization against coronavirus, the fact of the matter is we are nowhere near the home stretch and all we can do is continue to maintain the discipline that this situation requires us to.

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