Vaccine

Question 1

Antibiotics resistance

Answer 1

– Many bacteria have developed the ability to
become resistant to antibiotics.
e.g. Methicillin Resistant Staphylococcus Aureus (MRSA)

The Causes
– Overuse
» Antibiotics have been used to treat infections eveb they
are not needed or not effective i.e. for the flu
– Misuse
» Not completing a prescribed course
» Using antibiotics not prescribed

Question 2

Vaccine
Historical
Edward Jenner Perspective

Answer 2

1760-70 The Jennerian era.
1875-1910 Dawn of immunological science.
1910-30 Early bacterial vaccines, toxins and toxoids.
1930-50 Early viral vaccines: yellow fever and Influenza.
1950-1970 The tissue culture revolution: poliomyelitis,
measles, mumps and rubella.
1970-1990 Dawn of the molecular era: hepatitis B,
streptococcus pneumonia, haemophilus
influenza B (Hib)
Today Glycoconjugate, rotavirus vaccine, etc.

Question 3

Vaccine

Answer 3

• A vaccine is an immuno-biological
substance designed to produce specific
protection against a given disease.

Question 4

• Mechanism of vaccination:

Answer 4

• Passive immunization:
– Protective Abs --> non immune recipient
– No immunological memory
• Active immunization:
– Induction of adaptive immune response,
with protection and memory

Question 5

The Adaptive Immune system

Answer 5

Cellular immune system: destroys intracellular pathogens (such as virus-infected cells and mycobacteria) using T cells.

Humoral immune system: acts against bacteria and viruses using immunoglobulins (antibodies) –produced by B cells.

Question 6

Vaccination strategies

Answer 6

• Vaccination is a method of giving antigen to stimulate the immune response through active immunization, without causing disease
• A vaccine is “antigenic” but not a “pathogenic”

Question 7

Types of vaccines

Answer 7

Live Attenuated vaccines
•Smallpox
•BCG
•Typhoid oral
•Plague
•Oral polio
•Yellow fever
•Measles
•Mumps
•Rubella
•Intranasal
Influenza
•Typhus

Killed Inactivated vaccines
•Typhoid
•Cholera
•Pertussis
•Plague
•Rabies
•Salk polio
•Intra-muscular
influenza
•Japanese
encephalitis

Toxoids
•Diphtheria
•Tetanus

Cellular fraction vaccines
•Meningococcal polysaccharide vaccine
•Pneumococcal polysaccharide vaccine
•Hepatitis B polypeptide vaccine

Recombinant vaccines
•Hepatitis B vaccine

Question 8

Scheme of immunization

Answer 8

• Primary vaccination
– One dose vaccines
(BCG, variola, measles, mumps, rubella, yellow fever)
– Multiple dose vaccines
(polio, DPT, hepatitis B)
• Booster vaccination
To maintain immunity level after it declines after some
time has elapsed (DT, MMR).
• Deep subcutaneous or intramuscular route (most vaccines)
• Oral route (sabine, oral BCG vaccine)
• Intradermal route (BCG vaccine)
• Scarification (small pox vaccine)
• Intranasal route (live attenuated influenza vaccine)

Question 9

Properties of an ideal vaccine

easy to define, difficult to achieve

Answer 9

• Give life-long immunity
• Broadly protective against all variants of organism
• Prevent disease transmission
• Rapidly induce immunity
• Effective in all subjects (the old & very young)
• Transmit maternal protection to the foetus
• Require few immunisations to induce protection
• Not need to be administered by injection (oral,
intranasal, transcutaneous)
• Stable, cheap & safe

Question 10

WHO important goals

Answer 10

• 80% immunization coverage of all vaccines in all
areas;
• Develop new vaccines:
– Hepatitis B vaccine
– Haemophilus influenzae type b (Hib) vaccine
– Japanese encephalitis vaccine
– Yellow fever vaccine
– Pneumococcus vaccine
– Meningococcal vaccine
• Prevent the majority of
 those 2.3 million
 avoidable deaths
 each year.

Question 11

The Bad

Answer 11

Vaccines “rocky” past
The Cutter IPV incident
Vaccine associated paralytic polio
Swine flu vaccine and Guillain Barre syndrome
Local side effects: swelling, redness
Systemic side effects: fever, pain, allergic reaction
MMR: thrombocytopenia, febrile seizures
Guillain-Barre: MCV4

Question 12

Vaccines vs Drugs

Answer 12

Similarities
Vaccines are also medicines
Potential for adverse effects
Multiple ingredients
Potential for interaction with disease and other medicines
Also need to comply with standards of safety, efficacy and quality

Differences
Drugs kill invaders of foreign pathogens
Drugs inhibit the growth of pathogens
Vaccines generate memory cells
Vaccines train immune system to face various existing disease agents

Question 13

passive barrier

Answer 13

skin
mucous
stomach acid

Question 14

innate immune system

Answer 14

• complement response
• phagocytes
• granulocytes

Question 15

adaptive immune system

Answer 15

lymphocytes ( b cells and t cells)