What are Vaccines???

Vaccines: 

Generally, vaccines are given to persons in order to prevent them from current or future diseases. The procedure of giving vaccine to a person is termed as vaccination. It is a very successful, safe and simple method of protecting people from harmful infections and diseases. The primary purpose of vaccination is to develop acquired active immunity in human beings. Biologically, a vaccine is a substance which contains weakened or dead microorganisms (viruses, bacteria, etc.), toxins or some mRNA. It develops immunity by stimulating the production of antibodies in the body.

Discovery: 

Edward Jenner, a British Physician, discovered the world’s first vaccine. In 1796, Edward Jenner intentionally infected a boy with cowpox by injecting pus cells. After the boy recovered from cowpox, Jenner then injected him with pus cells from a smallpox patient. Remarkably, the boy did not contract smallpox, demonstrating that deliberate cowpox infection offered protection against the disease. This method was coined “vaccination,” with the immunization substance being called a “vaccine.”

Types of Vaccines: 

1. Live-attenuated vaccines are formulated using a weakened version of a virus or bacteria that poses minimal risk to individuals with robust immune systems.
2. Inactivated vaccines feature a deactivated form of a virus or bacteria.
3. Subunit, recombinant, polysaccharide, and conjugate vaccines target specific elements of a virus or bacteria, such as proteins, sugars, or outer coverings.
4. Toxoid vaccines leverage toxins produced by viruses or bacteria to stimulate immunity.
5. Messenger RNA (mRNA) vaccines equip cells with instructions for generating a virus’s protein.
6. Viral vector vaccines transport genetic material to cells, guiding them in producing a virus’s protein.
7. Biosynthetic vaccines incorporate synthetic components that closely mimic those of a virus or bacteria.

Mode of Action of Vaccines: 

Pathogens possess distinct proteins called “antigens.” Once they enter the host’s blood, these antigens stimulate the host’s immune response, prompting the creation of “antibodies.” These antibodies bind to the pathogens, deactivating and removing them. Additionally, the immune system generates “memory cells” that travel in the blood, offering lasting defense against future infections by the same pathogen. When a vaccine, containing weakened or inactive pathogens, is injected into the blood, it triggers the white blood cells. B-lymphocytes, a specific type of white blood cell, recognize the weakened or inactive pathogens as foreign intruders and start producing antibodies to combat them. These antibodies remain in the blood, forming a barrier against potential pathogen invasions. If real pathogens breach the blood, the existing antibodies promptly identify and eliminate them, preventing infection.

Methods of giving Vaccines:

The primary way to administer vaccines is through injection, although some are orally or nasally administered.

Some Diseases and their Vaccines: 

Note: Vaccination is mandatory for children before school enrollment. Immunizing children has significantly reduced the prevalence of numerous previously widespread illnesses such as whooping cough, polio, smallpox, among others.