Vaccines: Deciphering the magical potion

"I wonder why scientists are not able to create a vaccine for a virus which can be killed by a 10 rupees soap!", read one of the memes over the pandemic. The message made me laugh and feel sad at the same time. The last few months have been tragic, fearful, and chaotic…to say the least. The world has been in the grip of a virus, with lock-downs enforced in numerous countries. The cases are heading north with no respite in the near future.

Vaccine has been a topic of discussion in recent times. Though theories on vaccines being in different stages of development are doing rounds, it is highly unlikely that one will be available for general use by the end of 2020. Though, I sincerely wish it does. But do you know how vaccines work? How do they create a protective shield around our body? And how did the name 'vaccine' come into existence? Continue reading.

How was the name 'Vaccine' coined?

Let us commence by reading about the word itself. 'Vaccine' is derived from the Latin Vacca, meaning 'cow' and Vaccinus meaning 'of or from cow'. Further, Vaccinia means Cowpox virus.

Now the related snippet of history: The first vaccine given to a human(in-fact an 8 year old boy) was for Vaccinia virus (cowpox), to fight against a similar disease 'smallpox'. The boy was then exposed to Smallpox multiple times, but he remained immune. And since then, inoculation is referred to as Vaccination and the potion is called Vaccine.

Image by Miguel Á.Padriñán from Pixabay

What is a Vaccine and how does it work?

Before learning about the functioning of vaccines, let us understand our immune system. While not all pathogens are really harmful, some of them may be quite dreadful. Whenever any bacteria or viruses make headway into our body, the White Blood cells(WBCs) come together to fight them. This is akin to Avengers being called up in case of an alien invasion. But how do WBCs recognize these germs in the first place? Good question. It is via the alien shape of the pathogen (typically, proteins or sugars on the virus/bacterial surface), which helps in identifying that the body is under attack.They don't seem, so to say, 'earth-like'.

Coming back to the battle: Seeing the intruders, WBCs start releasing antibodies. To kill these malicious foreigners, a perfect shaped antibody has to be created; which may take a few days, at times. Once available, the production of those antibodies is sped up and jointly they start fighting the bacterium/virus by sticking to the pathogen surface, ultimately weakening or destroying them. A few WBCs also memorize these foreigners, as a way to fight them in their next attack. Referring again to the world of superheroes, it is similar to Avengers remembering to take the Infinity stones in the 'End game', as the only way to defeat Thanos.

Now to the original question: how do vaccines work? Let's shed light on it. Vaccines capitalize on the natural immune system of our body. They work like a simulator or a training module for the body cells. How? A vaccine dose releases weakened/dead cells/toxins from the pathogen in our body, good enough to be seen as aliens attacking our system. It triggers the natural immune system and WBCs get into action, killing and memorizing the marauders. Since the cells are weakened or dead, they do not cause any harm to the body. However, our immune system gets trained to combat them in the eventuality of an actual attack, since they have now memorized these antigens. This ensures rapid action without us knowing about the attack. One more analogy to Avengers (can't help as I'm a big fan): When Loki came to the earth for the first time, he did create some ruckus. But later on, his further invasions are deftly handled by Hulk/Iron Man/Thor, since they remembered how to fight him.

Classification of Vaccines:

Basis the type of mock/trainee cells introduced in the body, vaccines are classified as:

1. Live Attenuated vaccine: They introduce a weakened version of the bacterium/virus in our body but results in a strong immune system. Live Vaccines are used for Measles, Rotavirus, Smallpox, Chickenpox etc.
2. Inactivated vaccine: It contains dead cells of the pathogen & hence demand several doses over time. Generally used for Hepatitis A, Rabies, Polio.
3. Subunit/Conjugate vaccine: As the name goes, these vaccines use a specific subunit (protein/carbohydrate/sugar) of the germ as an invader. Typical examples are: Hepatitis B, Pneumococcal disease
4. Toxoid vaccine: These vaccines are made up of the inactivated/dead toxin generated by the pathogen, instead of the germ itself. Hence, the derived name. Diphtheria and Tetanus are such vaccines
5. DNA vaccine: It uses the DNA strands of the bacterium/virus while discarding the rest of the parts.           

Is Vaccine given to a healthy person or to a patient?

This question, though obvious to many, is quite an important one. A vaccine is given to a healthy person as a prophylactic measure, i.e. to keep us immune to diseases. That said, a new concept called Therapeutic vaccine has come up, though still it is in infancy. A therapeutic vaccine is intended to be given to the patients to minimize the pathogen impact. However, these vaccines help to provide impetus to the immune system by targeting the rogue aliens.

Nerd Notes:

1. Edward Jenner, an English physician, is credited with creating the world’s first vaccine in 1796.
2. The first lab created vaccine was Louis Pasteur’s 1879 vaccine for chicken cholera
3. Quarantine practice dates back to the 14th century (Read more about Quarantine origin).
4. Majority of the work in Therapeutic vaccine field is being done for treatment of cancer cells.

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Thanks for reading. Keep smiling, practice yoga and a very Happy Father's day - 2020. 

Important thing: If you have still not been vaccinated, please get jabbed at the earliest. Take care!

- Prakhar