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Vaccination Station: The making of the vaccine7 min read

December 14, 2020 5 min read


Vaccination Station: The making of the vaccine7 min read

Reading Time: 5 minutes

In this second of a three-part series on vaccines, let’s explore what goes behind creating one.

Vaccines definitely go through a long long journey. Once scientists think that they’ve discovered one, they can’t just give it to people like candy. They have to test it and then test it some more and then a little more and Jiminy crickets! You can never have enough testing. So, how does all this testing happen? Well, it all happens in a series of phases; let’s get into it step by step.

Follow these steps to get your vaccine approved.

Step 1

Scientists identify the virus and understand it. Take a look at what happened when Chinese scientists used supercomputers and advanced technology to create a clearer picture of the virus. 

Anatomy of a killer - Understanding SARS-CoV-2 and the drugs that might  lessen its power | Briefing | The Economist
The structure of the SARS-COV2 (Covid19) virus. Image: Britannica

Step 2

person in white long sleeve shirt holding green and white labeled can

Experts across the globe who study viruses take a look at it and begin to understand how the virus works. Then, with the help of computers and their past experiences and studies, they develop medicines and think of ideas for vaccines. Various companies, universities, and organizations take a crack at it, and they conjure up hundreds of possible vaccines. Each vaccine has a different mode of attack, and it is finally time to test these things.

<<Image: CDC via Unsplash

Step 3

Image: GIPHY

The long-winded trial begins. Usually, trials go on for years and years, but, thanks to technology and some good fortune, the Covid 19 vaccines are tumbling past at warp speed.

Pre-clinical trials: Pre-clinical trials are the first stage of vaccine trials. Scientists conduct these trials before they test the vaccine on humans.

Lab Testing:

Why a coronavirus vaccine takes over a year to produce – and why that is  incredibly fast | World Economic Forum
A scientist testing the Covid19 vaccine in a lab. Image: World Economic Forum

During this stage, scientists test the vaccine on live cells in a lab. Does it clean the virus out of the cells? Does it prevent the virus and not harm the cells? Is the vaccine good enough to create resistance to SARS-Cov2? If the answer to all this is yes, scientists move on to the next phase of the pre-clinical trials.

Step 4

Animal Testing:

Scientists test the vaccine on little animals like rats followed by larger animals like human’s close relatives, chimpanzees. If the vaccine is safe for the animals and doesn’t harm them while also preventing infection from Covid 19, the candidate moves forward. If, however, the vaccine is unsafe or ineffective, it is abandoned.

Labs scramble to find right animals for coronavirus studies - STAT
The coronavirus vaccine has been tested extensively on ferrets as they are extremely sensitive to Covid19. Image: STAT

Owliver’s Obscure Observation: Recently, scientists abandoned an Australian vaccine as their trials found that it wasn’t safe. Even though this may seem like bad news, it is in fact great news as it indicates that the trials are being conducted well and carefully!

Step 5

Clinical Trials: Finally, after the vaccine has been declared safe and effective on large numbers of animals, it is ready for human testing. Human testing occurs in three phases.

78 vaccines are currently being tested on human beings!

Phase 1

Scientists inject a small number of healthy human volunteers with the test vaccine. Through these tests, scientists find out how safe the vaccine is for humans and how much of the vaccine is required to prevent infection. Most coronavirus vaccines require two injections, a few weeks apart. If no one falls seriously ill in this stage of the trial, the vaccine candidate goes on to the next phase of human testing.

Owliver’s Obscure Observation: During the second and third phases and occasionally, even during the first phase of human trials, scientists perform what are known as randomized clinical trials. Candidates are either given saltwater vaccines or the real deal. The group of people that is given the saltwater vaccine is known as the control group. 

Why do we need a control group? Well, it helps scientists know precisely how effective their vaccine is. Half the healthy volunteers get injected with simple saltwater, and half get the vaccine. If about the same number of people from both groups get infected over some time, then scientists can see that their vaccine makes no difference. If more people in the vaccine group get infected, that’s no good either. However, if a lot more people in the control group get infected, then the vaccine is obviously working.

Step 6

Phase 2

Covid-19: Will a vaccine give us our old lives back? - BBC News
In Phase 2 Clinical Trials the vaccine is tested on people of different ages and ethnicities. Image: BBC

After scientists declare that the vaccine is safe, it is tested for effectiveness. In this phase, scientists choose people of different ages and from various communities to take the vaccine. After this phase, scientists know who the vaccine is safe for. Is it safe for only a small group of people or for the population at large? 

Step 7

Phase 3

In the final stage, the vaccine is tested on a large pool of people. For Covid19, most phase 3 trials had around 30,000 people enrolled. Once a certain number of volunteers fall ill, scientists take a look at which group they belonged to. If most people that got infected belonged to the control group, then scientists submit their vaccine for approval. The number of people that get infected within the vaccinated group is also extremely crucial. If less than 60% of the participants fell ill, the vaccine is considered ready-to-use. In fact, some of the Covid-19 vaccines, thanks to modern technology and science, are over 90% effective!!

>>Image: GIPHY

Owliver’s Obscure Observation: Many vaccine companies have combined Phase 2 and 3 of their Covid19 vaccine trials. They did this to make the vaccine available faster. And, since the vaccine is already determined to be safe after Phase 1, this wasn’t dangerous for the volunteers.


Once scientists have studied their trials and participants, they ask governments for approval. They share all the information they have gathered along with their own thoughts and conclusions. Governments put together groups of expert doctors and scholars who don’t belong to any vaccine developing team or company to review this information. These experts determine whether these vaccines are safe, effective, and affordable enough to be given to the country. So far, only Canada and the U.K. have approved vaccines for public use. India is expected to approve a vaccine within weeks!


Decrypt this message to unlock a fascinating fact about vaccines!

Alright then, we’ll see you soon in the 3rd part of this series. Catch Part 1 here.

With Excerpts From: New York Times, CDC, Nature