Vacines - Bacterial And Viral Flashcards
What is neisseria meningitids?
A gram negative bacterium that can cause meningitis and other forms of disease including life threatening sepsis
Six serogrups responsible for almost all diseases in the world:
A
B
C
W-135
X
Y
Has a vaccine - Men C vaccine
What are the 2 current MenC vaccines in the UK schedule/
HiB/MenC combined vaccine (Menitorix)
- given at 1 year
- MenC is conjugated to TETANUS toxoid
Men ACWY (Menveo, Nimenrix)
- given at 14 years
- Menvo = polysachaarrides from A,C,W135, Y conjugated to diphtheria toxoid
- Nimenrix = they are conjugated to tetanus toxoid
Why is it difficult to develop a MenB vaccine?
Because the polysacharride too similar to that on some human cells
A vaccine was developed in 2015
- not worth financial cost and risks of vaccination
- free outrage cost analysis was done again and the vaccine was approved as worth introducing
What is the MenB vaccine (Bexero)?
Made from 3 major proteins on the surface of most meningococcal bacteria, combined with outer membrane of 1 MenB strain
Produced in E. coli cells by recombinant DNA technology
Absorbed on aluminium hydroxide
Approved September 2015
What is haemophilia influenzae?
99% Type B
Gran negative bacteria - a bacterial meningitis
Paediatric diseases - 6 month - 3 years
Can lead to Arthuritis or meningitis
What is the HiB vaccine?
Vaccine for type B haemophilia influenza
Type B capsule polysacharriide linked to conjugate
- DIPHTHERIA TOXOIDS
- TETANUS TOXOIDS
- MENINGOCOCCAL OUTER MEMBRANE PROTEINS
What is diphtheria?
Caused by bacterial toxins from corynebacterium diphtheriae
Inhibits protein synthesis in eukaryotes
Grows in the pharynx, larynx and nose - non-invasive so does not spread
Toxin produced locally but acts at a distance
- absorbed by lymphatics = damages heart, kidney, nerves, adrenals
- forms a gelatinous exudate kills epithelial cells and polymorphs
- forms a necrotic exudate = ulcers form
What is the vaccine for Diphtheria toxin?
DTaP or dTaP
Diphtheria toxin is treated to make toxoid which is not toxic but immunogenic
Combined with albumin salts adjuvant
Given as a combined vaccine DTaP (higher amount of toxoid) or dTaP
What is tetanus?
Caused by a toxin released from clostridium tetani
Gram positive rods - soil dweller - anaerobe
Tetanus toxin is a neurotoxin that inhibits release of neurotransmitters from inhibitory inferons, which interact with motor neurones - Violent spastic paralysis
What is the vaccine for Tetanus?
DTaP and Tdap
Tetanus toxoid is treated to convert it into a toxoid, loss of toxicity but not immunogenicity
Combined with aluminium salt adjuvant
what is whooping cough (Pertussis)?
Caused by bordetella pertussis - release pertussis toxin which is a virulence factor in pathogenesis
Profound leukocytosis (rise in WBC)
A cough lasting weeks often with “whoop noise”
Can result in death, especially in newborns
Bacterium adheres to ciliated epithelial cell in upper Respiratory tract and multiples - may decend to lungs in infants
What is the vaccine for whooping cough-pertussis?
DTaP vaccine
Contains:
pertussis toxoid,
filamentous haemoglutinin,
pertactin (promotes adhesion to cells)
Blocks adhesion ad neutralises toxin
Who is given the influenza vaccine?
- At risk population and key staff (NHS)
- all hose bed 65 years or over
- pregnant women
- all children 2—10 years old
What is the aim of the influenza programme?
Protect those who are most at risk of serious illness or death should they develop influenza
What are the 3 types of influenza?
A
B
C
A and B most common
what causes variation in influenza?
Haemaglutinin - 18 types
Neuraminidase - 11 types
Antigenic drift mutation + selection in surface proteins
Antigenic shift - green reassortment between antgenically different strains producing hybrid progeny
What is the flu vaccine composed of?
Usually are quadravalant - containing 2 sub-types of influenza A and 2 sub-types of influenza B
Vaccine will change every year based on WHO recommendation for predominant circulating strains
Grown in embryonated hen eggs or in cell culture and are inactivated - all but one vaccine in the UK are inactivated
The one live vaccine is Fluenz tetra - given as a nasal spray and attenuated so that is only replicated in the cold (in nasal passages but not rest of the body
What determines the effectiveness of the influenza vaccine?
Variable by year/age group
Antigenic drift an shift
Manufacturing issues can occur
What is pneumococcal infection?
Caused by streptococcus pneumoniae
What is a invasive disease?
Where the bacterium can be isolated from blood or fro another location which is normal sterile
What is the pneumococcal polysaccharide vaccine PPV23?
A polysacharrde vaccine
Polysaccharides from 23 stereotypes used in vaccine (PPV) for at risk adults and children over the age of 2
Children under 2 can’t are a long-lasting protective immune response to polysaccharide vaccine - NEED. CONJUGATED VACCINE
What is Pneumococcal conjugate vaccine: PCV 13?
Polysaccharides from 13 most common capsule types
Conjugated to diphtheria toxoid
What is the human papillomavirus HPV?
Over 40 types
High risk types (16,18) - lead to cervical cancer
Low risk types (6.11) - genital warts
What are the two licensed vaccines for HPV?
Cervarix: Protects against HPV 16,18
Gardasil: protects against HPV 6,11,16,18 - used now for protection against cervical cancer and genital warts
Clinical trails show high efficacy, well tolerated
Scheduled: 2D she’s offered to Boyd and girls 12–13 years old
What is neonatal tetanus?
Disease of the 8th day in some developing countries due to infection of the umbilical chord
Tetanu toxoid vacccine to mother in late pregnancy
What are the vaccines approved for pregnant women in the UK?
- DTaP/dTaP — protect newborn infants from whooping cough
- Flu - mother and baby protection - earlier the better - baby could be still born or born prematurely if mother has flu
How can tuberculosis be diagnosed?
The mantoux test
Tuberculin injected in trader ally and measured after 72 hours
If you have TB or have had TB, memory T cell will be reactivated, cytokines ill be secreted and a local inflammatory response will occur
Red bumble on the skin if the person has TB
Results will have to be interpreted carefully and depend on risk factors of individual
ALSO BE GIVEN CHEST X RAY
What two vaccines are not approved in the UK and why?
Tuberculosis vaccine
- from 2005 children no longer have to be vaccinated against TB
Chickenpox vaccine
- vast majority of children recover quickly and easily
- Adult chickenpox is more servere
- therefore allowing children to develop they’re immune response/defence from a young age lessens the effects of contracting chickenpox in adulthood
- being exposed to chickenpox in adulthood boosts your immunity to shingles
