Vaccines Flashcards
What are active immunisations and give examples
Orally administered or injected antigens of a pathogen that stimulate an immune response and therefore provide immunisation over time (not immediate). There are different types of active immunisations and these include…
* Inactivated vaccines - Hepatitis A, Rabies
* Live vaccines - MMR (Measles, Mumps, Rubella), Varicella-zoster vaccines
What are passive immunisations
Vaccines that consist of antibodies that provide rapid, temporary protection without activating/stimulating the immune system. These include…
* Immune serum globulin
* Specific immunoglobulins
* Monoclonal antobodies
How are attenuated vaccines developed
Through a process called Serial passage with the aim of acheiving genetic roulette:
1. Virus/bacteria grown in tissue culture
2. Take sample and place in another culture
3. Replication occurs repeatedly leading to mutations
4. Mutation may lead to an non-virulent strain (attenuated pathogen)
In what circumstances are inactivated organisms used over live ones for vaccines
- When attenuation cannot be achieved
- Reversion to wild-type too likely
What agents can be used to deactivate viruses & bacteria
- β-propiolactone - Rabies, influenza
- Formaldehyde - Polio, Hepatitis A, Bordetella pertussis, yersina pestis
- Heat - Vibrio cholerae, Salmonella
- Colicin - E.coli
What is an adjuvant
A ingredient added to vaccines to enhance the immune response to the vaccine.
What are the key differences between living and non-living vaccines
- Non-living vaccines require adjuvant (living do not)
- Non-living are expensive to develop and produce (living are cheaper)
- Multiple doses required + boosters for non-living (whereas living does not)
- Living have potential of reverting to wild-type
- Living require cold chain of storage
What are the favourable factors for global eradication of a disease
- Disease must only be transmitable among humans (No re-invasion from animals)
- No long term carreir status (including latent diseases)
- Disease is easily clinically recognised
- One or very few strains of the disease exist
- Has to be cost-effective
What are the advantages/disadvantages of mRNA vaccines
Advantages:
* Production speed
* Cost effective
* Induction of humoral and cellular immunity
Disadvantages:
* Fragility of mRNA molecules requires cold chain distribution & storage
What are non-routine vaccinations
Vaccinations that are not in the vaccination schedule but are recommended for high risk individuals and travellers (that also fit into that category)
What is the mantoux test
A screening test that detects whether a person has been exposed to TB. It consists of intradermally injecting the individual with PPD tuberculin. The results will determine what the next steps may be.
What is the Hep B vaccine scheudle for adults
The vaccine is given at 0, 1 and 6 months with a booster after 10 years
Hep B vaccine schedule for babies
The vaccine is given at 2 daysold, 1 month and 2 months followed by a blood test and booster dose at 1 years old
Who is the pneumococcus vaccine offered to
- Elderly (>65)
- Adults & children at increased risk
Who is the varicella-zoster (chickenpox) vaccine offered to
It is offered to health care workers who have no evidence of immunity (have not contracted it before) and individuals who also haven’t had it before
