L54 Vaccines Flashcards
- New this year: COVID19 vaccines (35 cards)
Vaccine is a type of active/passive immunisation.
Briefly describe the onset and prophylactic value.
Active
- Ag given, stimulate Ab
- rely on active immune response
- Slow onset: few weeks to develop immunity
- Pre-exposure prophylaxis
Pooled immunoglobulin e.g. IVIG / virus-specific Ig e.g. HBIG, VZIG, palivizumab (synthetic IgG against RSV) are examples of ______immunisation.
Briefly describe the onset and prophylactic value.
- immediate but short duration (1-3 months)
- post-exposure prophylaxis
Basic principle of vaccination?
Use an artificial antigen to provoke adaptive immune response, so that the immune system is prepared and ready for a rapid and robust response when it encounters a real infection in the future
Give examples of vaccines that are live attenuated. (8)
- Viral
- MMR (measles, mumps, rubella)
- Rotavirus
- Varicella (Chickenpox)
- Vaccinia (Smallpox)
- Yellow fever
- Oral polio - Bacterial
- BCG
- Oral typhoid
Inactivated vaccines can either be whole for fractional.
One type of fractional vaccine is protein-based subunit vaccine. Give examples (3).
- Influenza
- Hepatitis B
- Acellular pertussis
Other than subunit protein-based fractional vaccine, there is toxoid protein-based fractional vaccine. Give examples. (2)
Tetanus
Diphtheria
PPV23 (pneumococcal vaccine) is an example of which type of vaccine?
Polysaccharide-based pure fractional inactivated vaccine
Examples of inactivated vaccines in general? (4)
- Hepatitis A
- Flu (shot only)
- Polio (shot only)
- Rabies
Example of subunit vaccines (4)?
- Influenza
- Hepatitis B
- HPV (Human papillomavirus)
- Rotavirus
What is live attenuated vaccines?
Attenuation achieved by? (4)
Attenuated strain replicates to a small extent without causing diseases
- Culture under alternative conditions e.g. reduced temperature
- Delete mutants: delete genes that contribute to virulence
- Site-directed mutagenesis: selective mutations of virulence-associated sites
- Reassortment for segmented viruses (e.g. rotavirus)
What are the advantages of live attenuated vaccines? (3)
Disadvantages? (2)
Adv
- single dose
- long lasting
- good cellular immune response
Disadv
- Stability (cold temperature to retain viability)
- Possible reversion to virulence
MMRV (measles, mumps, rubella, varicella) is a type of ___________ vaccine.
Live attenuated
What is an inactivated vaccine?
Whole virus killed by physical (heat) or chemical means (formaldehyde, beta-propriolactone)
What are the advantages (2) and disadvantages(1) of inactivated vaccine?
Adv
- easy to prepare
- no risk of reversion to virulence
Disadv
- less immunogenic > multiple primary doses, booster dose, adjuvant required
Hepatitis A vaccine is a type of __________ vaccine.
Inactivated
Poliomyelitis vaccine is a type of __________ vaccine.
Inactivated
Hepatitis B vaccine is a type of __________ vaccine.
Subunit vaccine
Influenza vaccine is a type of __________ vaccine.
Subunit vaccine
What is a subunit vaccine?
Adv?
Disadvantages?
Contain only the antigenic fraction of virus
Adv: less reactogenic (less adverse reactions)
Disadv:
- Less immunogenic (than live attenuated and inactivated), requires adjuvant
Diphtheria and tetanus (of DTaP) are a type of _______ vaccine. Briefly describe.
It usually requires booster dose.
Toxoid vaccine is a chemically modified toxin which no longer toxic but still antigenic and can be used as a vaccine.
(Does not contain the pathogen)
List all possible adverse reactions of vaccines. (5)
- Mild, self-limiting
- pain, localised swelling,
- fever, malaise - Severe, immediate
- anaphylaxis, resuscitation should be in place - Rare
- Guillain-Barre syndrome (<1 per million)
- reversion to virulence (live attenuated)
Contraindicated/Precaution/Vaccine only if indicated?
Allergy in
a) Live attenuated vaccine
b) Inactivated vaccine
Both contraindicated
Contraindicated/Precaution/Vaccine only if indicated?
Pregnancy:
a) Live attenuated vaccine
b) Inactivated vaccine
a) Contraindicated
b) Vaccine if indicated
Contraindicated/Precaution/Vaccine only if indicated?
Immunosuppression:
a) Live attenuated vaccine
b) Inactivated vaccine
a) Contraindicated
b) Vaccine if indicated
