Vaccinology Flashcards
What is vaccinology?
Exploiting of immune memory to reduce infection from pathogens
Contrast the first and second dose of vaccines.
• first dose has high IgM, wanes after 6-7 days, high lag time before antibody responses and undetectable IgM after 60 days
• second dose is IgG or IgA (mucosal sites) response, with a qualitative improvement in Ab affinity due to affinity maturation, a quantitative improvement in Ab response, and decreased lag time
What is herd immunity?
The concept that pathogen spread stops after a certain % of the population becomes immunised.
Why do vaccines not complete protect an individual from getting the infection?
Many pathogens infect mucosal sites, which are difficult to administer vaccines to. Hence, systemically administered vaccines are unable to completely prevent infection, rather they prevent the individual from developing severe manifestations of the disease
Vaccine responses are heterogenous. What does this mean?
Different people have different immune responses generated based on factors like age and co-morbitidies
Rank vaccine types from most to least effective.
least: DNA/RNA vaccines –> subunit vaccines / viral protein vaccines –> pseudoviruses –> killed viral pathogens –> live-attenuated pathogens (MMRV and oral polio) :most
Rank vaccine types from least to most safe.
least: live attenuated pathogens –> killed viral pathogens –> pseudoviruses –> subunit vaccines / viral protein vaccines –> DNA/RNA vaccines
What are the compulsory vaccines in Singapore?
Measles (MMR) and Diptheria (tDAP)
Contrast the risks and benefits of live attenuated vaccines.
Risks: not safe for immunocompromised, may revert to virulence, tedious and expensive storage, must ensure no contamination
Benefits: stronger, long lasting responses, can confer mucosal immunity (if mucosally administered), relatively cheap
What are the risks of killed pathogen vaccines?
need to ensure killing is successful, weaker immune response than live attenuated
Weigh the benefits and costs of subunit/viral protein/DNA/RNA vaccines.
Benefits: safer for immunocompromised, can be combined in efficient vaccine cocktails
Costs: tedious production process, expensive, low yield, require adjuvants to work
What are the routes of vaccine administration?
• IM (IV leads to weak immune response)
• intranasal
• subcutaneous
• oral
• intradermal
What are adjuvants?
• chemicals that are immunogenic and hence stimulate an immune response
• used in subunit vaccines
• can be mineral salts (aluminium salt) or emulsions (more toxic)
• allow for antigen sparing and dose sparing
