Question

Select the correct option from the following regarding the various types of vaccines used in the prevention of disease.

• A. Inactivated vaccines - Attenuated form of the pathogen is introduced into the body
• B. Killed vaccine - live pathogens are introduced into the body which get killed once they reach inside the body
• C. Vaccines containing antigens- Only amino acids from the pathogen are introduced into the body
  
• D. RNA vaccine - mRNA sequence is introduced into the body

Answer 1

The correct option is D RNA vaccine - mRNA sequence is introduced into the body

Vaccines provide immunity against specific diseases.

Vaccines are preparations of live attenuated (weakened) pathogens, killed pathogens or antigenic extracts, which when introduced into the body of a living organism, elicit an immune response.

Inactivated vaccines (killed vaccines) make use of dead or killed pathogens to destroy disease producing capacity.

The intention of vaccination is to prevent the disease; hence, never living and active microbes/pathogens are given as vaccines. It will prove to be very fatal. In contrast, live attenuated vaccines use pathogens that are still alive, but are weakened.

Antigen-only vaccines or subunit vaccines make the use of the antigenic components of a pathogen like proteins, peptides or other immunogenic substances (carbohydrates along with proteins). These antigenic substances are produced in other harmless microorganisms using recombinant DNA technology and extracted for vaccine production. Hepatitis B vaccine is prepared by this method.

The RNA vaccine consists of an mRNA strand that codes for a disease-specific antigen. Once the mRNA strand in the vaccine is inside the body’s cells, the cells use the genetic information to produce the antigen. This antigen is then displayed on the cell surface, where it is recognised by the immune system and an immune response is generated.

Figure: Types of vaccines