CBM - Vaccines

Question 1

Vaccines

Types

Live attenuated

Answer 1

• LAV are derived from disease-causing pathogens (bacteria/virus), thee pathogens are weakened in the laboratory.
• They will grow in a vaccinated individual, but because they are weak, so they will cause no or very mild disease.
• LAVs stimulate an excellent immune response that is nearly as good as compared to an infection with the wild-type pathogen.
• Live microorganisms provide continual antigenic stimulation giving sufficient time for memory cell production.
• However because the vaccine is a live organism there is a chance that it can revert back to the pathogenic form.
• This can cause the disease in the patient or people around them.

Examples:

• TB
• Oral Polio
• Measles
• Rotovirus
• Yellow fever

Question 2

Vaccines

Types

Inactivated whole-cell (killed antigen) vaccine

Answer 2

• Inactivated whole-cell (killed antigen) vaccine
• Inactivated vaccines are made from microorganisms that have been killed through physical or chemical process

Examples:

• Whole cell pertussis
• Inactivated polio virus

Question 3

Vaccine Types

Subunit vaccine (purified vaccine)

Answer 3

• Subunit vaccines, like inactivated whole-cell vaccines, do not contain live components of the pathogen.
• They differ from inactivated whole-cell vaccines, by containing only the antigenic parts of the pathogen.
• These parts are necessary to elicit a protective immune response.

Example:

• Acellular pertussis
• Haemophilius influenzae type B (Hib)
• Pneumococcal (PCV-7, PCV-10, PCV -13)

Question 4

Vaccine Type

Toxoid Vaccine

Answer 4

• Toxoid vaccines are based on the toxin produced by certain bacteria (e.g. tetanus or diphtheria).
• The toxin invades the bloodstream and is largely responsible for the symptoms of the disease.
• The protein-based toxin is rendered harmless and used as the antigen in the vaccine to elicit immunity.
• To increase the immune response, the toxoid is adsorbed to aluminium or calcium salts, which serve as adjuvants.
• Toxoid vaccines are based on the toxin produced by certain bacteria (e.g. tetanus ordiphtheria).
• The toxin invades the bloodstream and is largely responsib le for the symptoms of the disease.
• The protein-based toxin is rendered harmless and used as the antigen in the vaccine to elicit immunity.
• To increase the immune response, the toxoid is adsorbed to aluminium or calcium salts, which serve as adjuvants.

Examples:

• Tetanoid toxoid
• Diptheria toxoid

Question 5

Vaccine Type

Mono and Polyvalent vaccines

Answer 5

• A monovalent vaccine contains a single strain of a single antigen (e.g. Measles vaccine),
• polyvalent vaccine contains two or more strains/serotypes of the same antigen (e.g. OPV).

Combination vaccines

• Some of the antigens a can be combined in a single injection that can prevent different diseases or that protect against multiple strains of infectious agents causing the same disease ( e.g. combination vaccine DPT combining diphtheria, pertussis and tetanus antigens)

Question 6

Vaccine Administration