Immunisation: How does it work?

List a benefit of live attenuated vaccines

- Strong, long-lasting immunity

List 2 drawbacks of non-live vaccines

- Weaker, short-term memory - Requires boosters/adjuvants

List 2 common adjuvants

1. Aluminium phosphate 2. Aluminium hydroxide

List 2 examples of subunit-recombinant protein vaccines

1. Hepatitis B 2. Papillomavirus

3 types of polysaccharide vaccinations

1. Some meningococcal vaccines 2. Some pneumococcal vaccines 3. Salmonella

What is an inactivated toxin vaccine?

Toxins chemically treated to eliminate toxicity whilst maintaining immunogenicity e.g. with formaldehyde

List 2 diseases that non-specific immunoglobulins are associated with

- Hepatitis A - Measles

List 2 diseases that specific immunoglobulins are associated with

- Hepatitis B - Rabies

List 2 ways a baby can access IgA from the mother

- IgA to baby via placenta - IgA to baby via breast milk

What are the benefits to passive immunisation?

- Rapid protection - Can give to all patients

What are the drawbacks to passive immunisation?

- Short lived - No memory - Cost

List 2 examples of subunit chemically purified vaccines

1. Acellular pertussis 2. Influenza

What are the 8 main live attenuated vaccines?

1. BCG (Tuberculosis) 2. Influenza 3. MMR 4. Polio 5. Rotavirus 6. Typhoid (oral) 7. Yellow fever 8. VZV

List 2 examples of inactivated toxin vaccines

1. Diphtheria 2. Tetanus

3 examples of conjugated polysaccharide vaccines

1. H. influenzae 2. Pneumococcal 3. Meningococcal

List 3 contraindications for vaccines

1. History of anaphylaxis to previous vaccine/vaccine component 2. Immunosuppression 3. Pregnancy

List 3 benefits of active immunisation

1. Immunogenic: resembles a natural infection 2. Replicates at site of infection: mucosal immunity 3. Spread between contacts e.g., polio

List 3 examples of inactivated vaccines

1. Inactivated polio 2. Hepatitis A 3. Rabies

List 3 adverse effects of vaccinations

1. Local reactions: pain, swelling, redness 2. General systemic effects: fever, headache, malaise 3. Rash e.g., MMR, VZV

List drawbacks to active immunisation

1. Potential for vaccine strain infection/disease 2. Not suitable in pregnancy 3. Need mature adaptive immune system

List 3 aims of immunisation

1. Prevent disease 2. Prevent infection 3. Outbreak control/eradication

List 3 causes of primary vaccine failure

1. Vaccine factors e.g., administration error 2. Host factors e.g., immunodeficiency 3. Inappropriate vaccine schedule

List 3 examples of exposures that can be treated via immunoglobulins

1. Wounds at high risk of tetanus- specific immunoglobulin 2. Accelerated hep B vaccine course (+/- immunoglobulin) post needlestick injury 3.Potential rabies exposure- course of vaccine +/- specific immunoglobulin

Adenovirus vector vaccine

Adenovirus engineered to remove replication genes and replace them with a transgene of interest

What are adjuvants?

Agents that stimulate the immune system; increases immunogenicity

mRNA vaccine

Based on injection of mRNA that is translated in the cells of the recipient to produce the target antigen

List a benefit of non-live vaccines

Can give to high-risk groups

List a drawback of live attenuated vaccines

Can't give to high risk groups

What is a subunit-chemically purified vaccine?

Certain components of a pathogen are purified for use in a vaccine

What is active immunity?

Immunity developed after being exposed to an infection/getting a vaccine

What is a secondary vaccine failure?

Immunity develops initially following immunisation but with time immunity wanes

what is an inactivated vaccine?

Pathogen killed by chemical or physical processes

Polysaccharide vaccination

Purified bacterial polysaccharide - T cell dependent - Poorly immunogenic in young children

Conjugated polysaccharide vaccine

Purified bacterial polysaccharide linked to a protein

Example of adenovirus vector vaccine

SARS-CoV-2 (AstraZeneca)

Example of mRNA vaccine

SARS-CoV-2 (Pfizer & Moderna)

What is a live attenuated vaccine?

Serial passage in tissue culture

What is a subunit-recombinant protein vaccine?

Specific viral protein produced in a heterologous expression system

What is immunisation?

The process by which a person develops immunity to a disease-causing organism

What is immunogenicity?

ability to provoke an immune response

What is a primary vaccine failure?

failure of vaccine to stimulate any immune response

What is passive immunity?

the short-term immunity that results from the introduction of antibodies from another person or animal.