Paediatrics

Question 1

Vaccine definition

Answer 1

Pharmaceutical preparation of immunogenic substance or compounds that induce active immunity against a particular disease.

Question 2

Active immunity

Answer 2

Adaptive/acquired
More specific
Allows memory

Question 3

Passive immunity

Answer 3

Not specialised
Temporary immunity
Little bit of immunity transferred i.e. via the placenta from mother to baby

Question 4

First generation vaccines

Answer 4

i. ) Live attenuated - reduced to a safe level but also causes an immune reaction (BCG, shingles, MMR)
ii. ) Killed/inactivated (whooping cough and polio)

Question 5

Second generation vaccines

Answer 5

Subunit vaccines i.e. protein/peptide - takes part of organism from surface or even a toxin from a microbe by converting to a safer form (diphtheria, tetanus)

Question 6

Third generation vaccines

Answer 6

DNA/mRNA vaccines by adiministering nucleic acids which codes for a particular protein which is an antigen allowing host cell to incorporate that protein

Question 7

Humoral vs cell mediated immunity

Answer 7

Humoral - Antibodies that engulf/neutralise pathogens circulating in the environment
Cell mediated - Cytoxic T cells and helper T cells kill pathogens inside body cells

Question 8

Antigen presenting cell

Answer 8

When macrophage engulfs a microbe is dissolves the components and displays the microbe antigens on its surface becoming an APC.

Question 9

Helper T cells

Answer 9

Activated by IL-1.

They identify APC and release cytokines which allow the activation of cytotoxic T and B cells.

Question 10

Cytotoxic T cells

Answer 10

Produced in the thyroid glands and they represent cell mediated immunity.
Infected body cells project molecules on its surface which signal they are infected and the cytotoxic T cell releases perforin to lyse and destroy the infected body cell.

Question 11

Cytotoxic B cell

Answer 11

Produced in the bone marrow and represent humoral immunity.
Cytotoxic B cell transforms into plasma cell which produces antibodies that bind to the microbial antigen. Antibodies attach to the microbe and signal to the cytotoxic T cell for destruction.

Question 12

Major histocompatibility complex

Answer 12

MHCI is present on all cells whereas MHCII is only present on immune cells. Antigens become complexed with MHCII and are projected on its surface.

Question 13

Immune cell activation

Answer 13

Helper T-cell is activated by IL-1.
CD4 receptor binds MHCII molecules whereas CD8 receptor binds MHCI molecules.
Binding of CD4 causes release of cytokines (IL-2,IL-4,IL-6)
This triggers activation of cytotoxic B cells and generation of plasma cells and antibodies.

Question 14

MMR vaccine

Answer 14

Protects against measles, mumps and rubella.
Complications of MMR: meningitis, encephalitis (swelling of the brain) and deafness.

Given at 1 year old and booster given at 3 years and 4 months.

Contains pork gelatin, human serum albumin (stabiliser), neomycin antibiotic to prevent bacterial growth and small amounts of egg protein.

Question 15

Meningitis B vaccine

Answer 15

Protects against meningococcal group B which is the most common.
Infection causes complications: meningitis, septicaemia (blood poisoning), severe brain damage, amputations and even death.

Vaccine offered at 2 months, 4 months followed with a booster at age 1 (12 months).

Question 16

Synthetic peptide vaccine

Answer 16

Advantage:

• Do not contain unrelated antigentic determinants inherently present in vaccine extracts obtained from microbes
• Do not produce undesirable effects

Disadvantages:
- Weak immunogens due to having a low molecular weight

Question 17

Vaccine adjuvant

Answer 17

A substance that helps increase immunogenic activity such as saponins, liposomes, immunostimulating complexes, MPL, MDP and DDA.

Question 18

How do virosomes work?

Answer 18

Virosomes are adjuvants made of viral envelopes with viral membrane components - haemaglutinin and neuraminidase. Isolate the genome and proteins, leaving the envelope alone putting the antigen inside. Haemaglutinin and neuraminidase are fusogenic materials and allow the antigen to enter the host cell by fusion.
- Hepatitis A and influenza

Question 19

Recombinant DNA technology

Answer 19

1. DNA from plasmid is cut open at specific site in sequence by restriction endonucleases.
2. Beneficial gene sequence is inserted into DNA sequence which is cleaved by restriction endonucleases.
3. New sequence is annealed by DNA ligase.
4. Insert the plasmid into the microbe cell and allow it to multiply.

Question 20

Vaccines at 2 months

Answer 20

• Diphtheria,tetanus,pertussis, polio,haemophillus influenza type b and hep B
• Men B
• Rotavirus

Question 21

Vaccines at 3 months:

Answer 21

• Diphtheria, tetanus, pertussis, polio, hib, hep b
• pneumococcal (13 types)
• Rotavirus

Question 22

Vaccines at 1 year:

Answer 22

• Hib and MenC/pneumococcal

- MMR/MenB

Question 23

Vaccines at 3 years and 4 months:

Answer 23

• Diphtheria, tetanus, pertussis, polio/MMR

- Flu vaccine (intranasal)

Question 24

Vaccines at age 12-13:

Answer 24

• HPV types 16 and 18 and genital warts caused by type 6 and 11

Question 25

Vaccines at age 14:

Answer 25

• Tetanus, diphtheria, polio

- MenACWY

Question 26

Transplacental IgG

Answer 26

Transplacental IgG blocks the child from their own immune response which begins to fall at the age of 2 months and isn’t low enough until the age of 1 year.

Question 27

HPV

Answer 27

Cause cancers and strains 16 and 18 are most responsible.

Vaccine given at age 12-13 with a booster 6-24 months later. If given after age of 15, three doses are needed.

Question 28

Tetanus

Answer 28

Caused by a toxin from a bacteria called clostridium tetani.
Affects the nervous system - muscular contractions of the jaw and neck and neck muscle spass.

Requires 5 doses - at 2 months, 3 months, 4 months and booster at 3 years 4 months and further booster at 14 years.