Vaccine and its types

A vaccine is a biological preparation that improves immunity to a particular disease.

A product that stimulates a person’s immune system to produce immunity to a specific disease, protecting the person from that disease. Vaccines are usually administered through needle injections, but can also be administered by mouth or sprayed into the nose.

 A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins. The agent stimulates the body’s immune system to recognize the agent as foreign, destroy it, and “remember” it, so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.

Vaccines are made using several different processes. Some of them are discussed below:

Type of vaccine

Live attenuated vaccines

Live, attenuated vaccines contain a version of the living microbe that has been weakened in the lab so it can’t cause disease. 

Measles, mumps, rubella (MMR combined vaccine)
Varicella (chickenpox)
Influenza (nasal spray)
Rotavirus

Inactivated vaccines

It is produce inactivated vaccines by killing the disease-causing microbe with chemicals, heat, or radiation. Inactivated vaccines usually don’t require refrigeration, and they can be easily stored and transported in a freeze-dried form, which makes them accessible to people in developing countries.

Hepatitis A, Influenza, Pneumococcal polysaccharide

Sub-unit vaccine

Instead of the entire microbe, subunit vaccines include only the antigens that best stimulate the immune system. 

Hepatitis B

Toxoid vaccines

Toxoid vaccines contain a toxin or chemical made by the bacteria or virus. They make a person immune to the harmful effects of the infection, instead of to the infection itself. 

Diphtheria and tetanus 

Polysaccharide Vaccines

Polysaccharide vaccines are a unique type of inactivated subunit vaccine composed of long chains of sugar molecules that make up the surface capsule of certain bacteria.

pneumococcal disease, meningococcal disease, and Salmonella Typhi

Biosynthetic vaccines 

Biosynthetic vaccines contain manmade substances that are very similar to pieces of the virus or bacteria. 

HIV