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How do vaccines work.
Types of vaccines and their working method.
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Vaccines are biological substances that help stimulate an immune response in the body, providing protection against specific infectious diseases. There are several different types of vaccines, each utilizing unique methods to achieve immunity. Here are some common types of vaccines and their working methods:
1. Inactivated or Killed Vaccines: These vaccines contain pathogens (viruses or bacteria) that have been inactivated or killed. They are unable to cause disease but can still trigger an immune response. Examples of inactivated vaccines include the polio vaccine and the hepatitis A vaccine.
2. Live-Attenuated Vaccines: These vaccines contain weakened forms of the pathogen. They are able to replicate within the body but cause only a mild or asymptomatic infection. This replication stimulates a strong immune response, providing long-lasting immunity. Examples of live-attenuated vaccines include the measles, mumps, and rubella (MMR) vaccine and the oral polio vaccine (OPV).
3. Subunit, Recombinant, or Protein Vaccines: These vaccines contain specific pieces of the pathogen, such as proteins or polysaccharides. They do not contain the complete pathogen and cannot cause the disease. They work by stimulating an immune response to the specific components of the pathogen. Examples include the hepatitis B vaccine and the human papillomavirus (HPV) vaccine.
4. Viral Vector Vaccines: These vaccines use a harmless virus (the vector) to deliver genetic material from the pathogen into the body’s cells. The genetic material instructs the cells to produce a viral protein, triggering an immune response. The Oxford-AstraZeneca COVID-19 vaccine and the Johnson & Johnson COVID-19 vaccine are examples of viral vector vaccines.
5. mRNA Vaccines: These vaccines contain messenger RNA (mRNA) molecules that provide instructions for cells to produce a viral protein. The viral protein stimulates an immune response. The Pfizer-BioNTech COVID-19 vaccine and the Moderna COVID-19 vaccine are examples of mRNA vaccines.
6. DNA Vaccines: These vaccines contain a small, circular piece of DNA that encodes a viral protein. The DNA is taken up by cells, which produce the viral protein and trigger an immune response. DNA vaccines are still under development and have not been widely used for human vaccinations.
These are some of the main types of vaccines and their working methods. It’s important to note that the development and approval of vaccines involve rigorous testing and evaluation to ensure safety and effectiveness.
