Microbiology 18 - Bacterial and viral vaccines Flashcards
(23 cards)
What is R0?
no of people that one sick person will infect on average / i.e. basic reproductive rate
What does R0<1 mean?
transmission is halted
What is meant by herd immunity?
vaccination of significant proportion of population p→ protection for individuals that are not immune
What is the equation for herd immunity threshold?
1 - 1/R0
the % of fully immune people required to stop spread
Summarise the immune response to vaccines
attenuated virus vaccine - T cell response very important in destroying infected cells
main goal to produce memory cells -> Memory B cells, Memory killer T cells, Memory T helper cells
Recall 3 vaccines that are made up of inactivated virus components
Mnemoninc: Inactivated Components of Pathogen
Influenza
Cholera
Polio (OPV = live attenuated; IPV = inactivated))
When should you defer inactivated vaccines?
Patient received systemic high dose steroids
Received immunoglobulins in the last 3 months
Recall some pros and cons of inactivated vaccines
Pros: stable, can’t cause disease
Cons: need several doses (short lasting), local reactions are common, an adjuvant is needed
Recall 2 examples of attenuated vaccines
MMR
Yellow fever
When should you avoid live attenuated vaccines?
pregnant women and immunocompromised patients
may revert to more virulent subtype
Potential contamination
Recall some pros and cons of attenuated vaccines
Pros: longer-lasting immunity - injection of whole pathogen means there can also be reaction to >1 antigen
Cons: Can revert to virulence
Recall 2 examples of toxoid vaccines
Tetanus
Diptheria
advantages and disadvantages of toxoid vaccines (inactivated toxin components)
How do subunit vaccines work?
Protein components of the microorganism or synthetic virus-like particles are used
They lack viral genetic material and are unable to replicate
Recall 2 examples of subunit vaccines
Hep B
HPV
How do conjugate vaccines work?
Poorly immunogenic Ags are paired with protein that is highly immunogenic (adjuvant)
What type of vaccine is the HiB vaccine?
Conjugate
What are examples of conjugate vaccines?
NHS bacteria vaccines
What are hetertotypic vaccines + e.g.?
Using pathogens that infect other animals but do NOT cause disease in humans or causes mild disease
BCG (bovine strain)
What is a viral vectored vaccine?
modified virus (e.g. adenovirus) to deliver genetic code for Ag
might reduce effectiveness if there is prev exposure to vector
What are some examples of viral vectored vaccines?
Ebola Janssen and AZ COVID vaccines
What are nucleic acid vaccines?
uses DNA/RNA from pathogen - e.g. Pfizer/Moderna
