Introduction:
Vaccines play an essential role in keeping us healthy. These help in providing us protection from serious and deadly diseases such as measles, and influenza. Vaccines have transformed the public health system tremendously since it was established in the 1960s. With the help of high vaccine programs in multiple countries, many of the diseases that were previously responsible for the majority of deaths in children have practically disappeared. The World Health Organization (WHO) estimates that every year around two to three million lives are saved by various vaccination programs.
What Are Vaccines?
Vaccines are injections, pills, or nasal sprays that instruct the body’s immune system to identify and protect against harmful germs. Vaccines make the body learn how to defend itself from deadly diseases. The immune response of the body to any vaccine may cause discomfort and tiredness for a day or two but the immunity may last for a lifetime for any specific condition. There are various vaccines available for diseases caused by viruses such as flu and COVID-19 and for bacteria-causing conditions like tetanus, diphtheria, and pertussis.
What Is the Function of Vaccines?
Vaccination is a way to build protective immunity without getting the body sick. Regardless different types of vaccines do this in different ways and aim to do the same thing such as -
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Vaccines expose the immune system to one or multiple proteins from the virus.
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This exposure instructs the immune system to make B cells (a type of white blood cell that makes antibodies).
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These B cells then make specific antibodies that fight off a specific virus.
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This vaccination process stimulates make memory B cells if the body is exposed to the virus again these B cells go into action right away and releases the antibodies that target the disease-causing cells.
What Are the Ingredients of Vaccines?
Vaccines contain certain ingredients other than viruses or bacteria of interest which include -
1. Adjuvants - These enhance the immune response by allowing lesser quantities of the viral or bacterial components to be used in the vaccine, for example, aluminum.
2. Stabilizers - These protect the proteins present in the vaccine from being spoiled during manufacturing and transportation for example gelatin.
3. Preservatives - They protect the vaccine from being contaminated. Nowadays, preservatives are usually used only in vials of vaccines that have more than one dose. Therefore most of the vaccines are available in a single dose and do not have preservatives in them. Thimerosal, a mercury-containing preservative, is the most commonly used preservative but is not present in childhood vaccines.
What Are the Types of Vaccines?
There are various types of vaccines such as -
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Live-attenuated Vaccines - These use a weakened form of germ that cause disease. These are very similar to the natural infection that they prevent by creating a strong and long-lasting immune response. Only one to two doses of most live vaccines can provide lifetime protection against disease.
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Inactivated Vaccines - In these vaccines killed version of a germ is used that causes a disease. They usually do not provide protection (immunity) as strong as a live vaccine. Therefore multiple doses called booster doses may be required to get long-lasting immunity against diseases.
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Toxoid Vaccines - This vaccine uses a toxin made by the disease-causing germ.
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Subunit, Recombinant, Polysaccharide, and Conjugate Vaccines - These vaccines use only specific parts of the germ such as protein, sugar, or casing. Therefore these vaccines provide a very strong immune response against the germ. These vaccines can be used in every patient with weakened immune systems and prolonged health problems.
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mRNA Vaccines - These vaccines use messenger RNA, which instructs the body cells to make protein to trigger an immune response.
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Viral Vector Vaccines - These types of vaccines use genetic material that gives instructions to the cells for making a protein of the germ.
All these vaccines work in different ways but cause the same immune response in the body against a specific antigen (disease-causing agent). Hence the immune response stimulated in the body helps in defending against certain foreign or harmful agents.
What Is the Immune Response After Vaccination?
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Vaccines consist of weakened, live or initiative forms of disease-causing agents such as viruses. Vaccines provide both short and long-term immunity (protection) against these infectious diseases.
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After the vaccine is injected into the body it acts like a weak disease-causing pathogen and the body initiates a response against that infection.
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The antigens present in the vaccine create an infection-like state in the body but are unable to cause any illness or harm to the body but do activate the immune system of the body to produce antibodies and T and B-lymphocytes against them.
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Post-vaccination there is the initial surge in immune cells and antibodies that act as the first line of defense against foreign agents such as viruses or bacteria.
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After this stage when the infection effect wears off the remaining cells formed during this process such as T and B lymphocytes will protect against future infection also. However, this may take a few weeks for the body to produce these disease-fighting lymphocytes post-vaccination.
Why Are Vaccines Important?
Vaccination is essential as it provides immunity against many serious conditions such as the recent pandemic COVID-19. So getting immunity from a vaccine is considered much safer than being sick with the disease. The vaccines not only protect a single individual but also protect the people around them via community immunity.
Community immunity, or herd immunity is the theory to help keep the communities healthy. The germ or infection can travel within a community much faster and may harm lots of people. Therefore getting enough people vaccinated against a certain disease make the spreading of the disease much slower or stops it. This provides immunity to the community against a certain infection.
Are Booster Vaccines Necessary?
This is commonly seen that for various infectious diseases, additional doses or booster doses are required to provide long-lasting immunity. This is a standard part of the vaccination schedule such as in case of tetanus, polio, or diphtheria. The booster doses help in elevating the level of antibodies and memory immune cells in the body and also strengthen their potency.
Therefore the data is collected from clinical trials and the immunity level is evaluated against a certain disease based on that booster doses are decided to provide long-term protection against infectious diseases, such as viruses and their variants.
Conclusion
Vaccines are another way to acquire antibodies against certain diseases. As these introduce one or more proteins from disease-causing agents like viruses which leads to the production of B cells that produces the antibodies against those foreign agents. Therefore, vaccination is must to prevent any harm. These are the safe and effective ways of protection from infectious diseases.
