Vaccines A Medical Marvel of Mankind
It was a cold winter morning of 1776; England was going through a Small Pox epidemic but a British Doctor named Edward Jenner had just created the world’s first vaccine for Small Pox by injecting an inactivated strain of Cow Pox in a 13-year-old boy and saved him from death. How? Let’s find out!
To understand vaccines, we need to understand how our immune system works. We have been reading since our high school about certain cells present in our blood.
Here, WBCs are responsible for providing us immunity to our body when its needed. These cells act much like soldiers in an ‘army’- ready to attack whenever needed. But sometimes we have some pathogens which escape these cells like ‘terrorists’ or they can replicate in large numbers which overwhelm our immune system and we fall ill.
Classification of Our immunity
Our immunity is broadly classified as
a) Cellular immunity
NK cells, which attack viruses, B and T lymphocytes which produce antibodies and recognize the antigen.
Finally, we have macrophages, which like to ‘eat’ the pathogen which kickstarts the whole immune reaction.
b) Humoral immunity
Here mainly the B lymphocytes produce antibodies like IgA, IgG, IgM, IgE, and IgD which is specific to a specific pathogen.
Overview of our immune system
We need to understand certain terms like- Antigens are those substances which are basically foreign substances that our body doesn’t like for example pathogens, pollen, dust etc. Antibodies are substances that produce immunological proteins which help immune systems to fight against the antigen.
So, what we need to know is that Macrophages are the first to recognize the pathogen and are ‘eaten’ up and presented to inactive T cells which becomes active via a process called as antigen presentation, its like police presenting a criminal to court after getting caught red-handed.
The active T-Cell then ‘presents’ itself to inactive B-cells and becomes active via certain immunological mediators like complement system etc. Once the B-cell is active it produces antibodies like IgM and IgG which help in further intensifying immune reaction.
How do vaccines work?
Vaccines usually contain a killed or an inactive pathogen or the toxin produced by the pathogen depending on how the disease manifests in the body. Coming back to Edward Jenner where he used Cow Pox which was very similar to Small Pox in its disease course and immune reaction but much less severe when compared to Smallpox.
So, he used this advantage and provided immunity to the kid hence making him free from Small Pox for life.
Types of vaccines
With the rapid advancement of science and technology in the 20th and 21st century, we have developed various types of vaccines keeping in mind about the safety and health of people in regulation with modern medical standards. These are the following types
a) Live attenuated vaccines
These vaccines use weakened strains of a pathogen such that they do not produce the disease but can produce the necessary response by the immune system and the person can stay healthy. Examples are oral polio vaccine, BCG, MMR vaccine, etc.
b) Inactivated/Killed vaccines
These vaccines use strains of pathogens that are killed by using heat and chemicals and vaccines are prepared out of it. Examples are the Rabies vaccine, COVAXIN, Influenza vaccine.
c) Subunit vaccines
These vaccines use single or multiple antigenic parts of a single or different micro-organisms, they have further types which include-
1) Toxoids
These vaccines create immunity by targeting the toxins produced by pathogen
thus creating immunity, examples are Diphtheria, Tetanus, etc.
2) Proteins
These target multiple antigenic sites of a pathogen. For example, Influenza has
certain proteins called haemagglutinin and neuraminidase which are both equally
responsible for causing flu. The influenza vaccine is prepared this way.
3) Recombinant types
They use recombinant DNA technology to derive vaccines, the latest vaccine being COVISHIELD, Hepatitis B.
d) Combination vaccines
Some vaccines are given in combination to provide immunity to many diseases at once and also to avoid burden to the general public. Some of them include DPT, MMR, etc.
Vaccine and COVID-19
Our technology has progressed so far that we had so many vaccines with various efficacy rates and we got our own homemade vaccines too.
Amid a lot of speculation and chaos, we have managed to control the pandemic through vaccination. Vaccinations that are available in India are COVISHIELD, COVAXIN, SPUTNIK V, ZYDUS, MODERNA vaccines. We have started vaccinating kids from ages 12 which is a great step.
As of February 15th, 55% of the population has been fully vaccinated and 69% of the population have taken their first dose. As we all know vaccination will help us end this pandemic.
Myths about vaccines
1) Myth: -The ingredients used in vaccine production are toxic for human health
Fact: - The ingredients used are actually the same fats, carbohydrates, and proteins that are in your diet. During the manufacturing process, and the vaccine is first purified and treated under UV before filling in the vial and sent to cold storage.
2) Myth: - Vaccines contain Microchips which is an invasion of privacy.
Fact: - This is funny because vaccines do not contain any Microchips, it's fake news. It’s advisable to not believe every piece of information on the internet and only trust authentic sources of information.
3) Myth: - Vaccines can affect my reproductive ability
Fact: - Vaccines do not cause any problem with human reproduction, if any such event occurs it would have been notified during the clinical trial. If found to be true the vaccine development would cease to exist even before entering the market
4) Myth: - I prefer to get infected with the natural pathogen rather than getting vaccinated
Fact: - As you read earlier, taking a vaccine will protect you from the disease without experiencing the painful symptoms of the disease. Moreover, getting a natural infection is a public health hazard as you could spread the infection to others
5) Myth: - Doctors don't care about us once we are given a vaccine
Fact: - It's an absolutely false claim. Always the person is advised to sit for 1 hour after vaccination to observe for any immediate problems like anaphylaxis, allergic reaction, low BP, pain, etc. You can always visit ANY nearby hospital to report AEFI (Adverse effects following immunization).
Advantages of taking vaccinations
1) They help in immunizing the person from deadly diseases.
2) It will help in producing herd immunity so it can protect people who haven’t taken their vaccination yet.
3) It helps in reducing the load on hospitals and health workers during an epidemic or a pandemic.
4) It helps to protect pregnant women and babies from diseases that will cause certain death like Tetanus.
Disadvantages of taking vaccines
Apart from a few rare adverse events ranging from minor reactions to major reactions like anaphylaxis, vaccines are safe for all groups of people. So, don’t believe any anti-vaxxer or any WhatsApp forwards which has fake information scaring you about vaccines.
I highly suggest you to have a look at the National Immunization Schedule as a fun activity to know the vaccinations that you took when you were a kid!
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