Vaccines Flashcards
Passive immunisation?
No immune response in recipient, by giving antibodies from a donor
Active immunisation?
Recipient develops a protective adaptive immune response
Reduction in mortality worldwide by vaccines is?
3 million per year
Variolation?
Smallpox virus, from South Asia, take fluid from pustules of recovering individuals and injected under skin of recipient
Jenner?
Fluid from cowpox lesions to prevent small pox infection,
Live attenuated vaccine
Examples of passive immunisation?
Immunoglobulin replacement in antibody deficient
VZV prophylaxis e.g during exposure during pregnancy
Anti-toxin therapies e.g snake anti-serum
What to do with VZV exposure during pregnancy?
VZV igG
What is herd immunity?
Vaccination of sufficient numbers impact the transmission dynamic so that even unimmunised individuals are at low risk
How do vaccines work?
By generating a long lasting, high affinity igG antibody response
What is in a vaccine?
Antigen
Adjuvants- immune potentiators to increase the immunogenicity of the vaccine
Excipients- diluents and additives for vaccine integrity
Subunit of vaccine?
Toxoids,
Capsular polysaccharide
MRNA
What is attenuation?
Removing pathogenicity of an organism by culturing ex Vivo in non-physiological conditions
E.g measles mumps rubella polio bcg cholera zoster. VZV live influenza
Disadvatage of live vaccines?
Become wild type, pathogenic e.g vaccine associated poliomyelitis 1 in 750,000
Storage problems, short half life
Immunocompromised individuals may develop clinical disease
Varicella zoster?
1 infection- chicken pox
Remains in sensory ganglia
Reactivation - zoster, in elderly causing neuropathic pain
How effective is VZV vaccine?
95%,
With 3-5% have mild varicella infection post vaccine
Safety concerns of VZV vaccine
Increase in zoster because less grandchildren with chicken pox so no boosting
Disease shift to unvaccinated adults- who have VZV less tolerated
How much reduction in zoster incidence after vaccination?
50%
What is poliomyelitis?
Enterovirus establishes infection in oropharynx and GI tract, spread to peters patch thru lymphatic
Haematogenous spread
1% develop neurological phase, replication in motor neurones leading to denervation and flaccid paralysis
Poliomyelitis vaccines?
Sabin oral polio vaccine- live
Salk injected polio vaccine- inactivated
Sabin oral polio vaccine?
Side effect associated paralytic polio,
Virus recovered from stool
Where does tb live?
In phagolysosomes of macrophages
What happens in TB immune response?
Macrophages present TB antigen to MTB specific CD4 T cells which secrete IFN-g this activates macrophages to encase tB in granuloma
What does tb look like on x ray?
Calcified lesion, Ghon focus
Tb vaccination done by?
BCH, done through mycobacterium bovis, aims to increase Th1 IFN-g cells responses to m bovis
Given by intradermal injection
How effective is BCG?
80 in disseminated TB and TB meningitis
How to kill organism?
Formaldehyde
What can’t killed vaccines do?
Illicit CD8 response
Examples of killed vaccines?
Hepatitis A
Influenza
Influenza antibody respond to?
Heamagglutinin and neuramidase surface antigens
Pandemic influenza cause by?
Major antigenic shift
Animal influenza combines with human influenza
Subunit vaccines include?
Corynebacterium diphtheria
Clostridium tetani
Bordatella pertussis
Stimulate antibody response, which neutralise toxin
Which organisms have thick polysaccharide coats?
Streptococcus pneumoniae and neisseria meningitidis
How to tackle polysaccharides capsules?
Vaccine conjugation, protein carrier attached to polysaccharide antigen
Recombinant protein subunit vaccine examples?
Hep b surface vaccine
HPV vaccine- empty particles
What do adjuvants do?
Bind to pattern recognition receptors on antigen presenting cells.
LPS alum
Novel adjuvants are?
Toll like receptor ligand e.g CPG repeats
Live vaccines benefit?
Give CD8 response
Boosting not required
Secondary protection to unvaccinated individuals
MRNA vaccines?
Codes for critical pathogen antigens
Given by vector lipid Nano-particle
E.g Pfizer and moderna
What is the aim of zoster vaccination?
Boost memory T cell responses to vzv
Viral vector?
Benign virus with genes to encode for antigen
AstraZeneca- simian adenovirus
