Vaccines: bacterial and viral Flashcards
What are vaccine schedules?
When to get specific vaccines by NHS according to age
What is DTP vaccine? what type of vaccine is it?
Diptheria, tentanus and polio
Based on toxoids - subset vaccine for polio is inactivated due to risk of reversion to virulence
Why is boosting required for Heb B and DTP?
Not live attentuated vaccines so needed
What is te vaccine type of PCV - pneumonococcal vaccine?
Conjugated polysaccharide - given twice for boosting too
What type of vaccine is given for rotavirus?
Oral live vaccine by syringe into babies mouth
Which type of vaccine is MMR?
live attenuated vaccine
Why is MMR vaccine given multiple times?
Already is live attentuated so doesnt need boosting
Given as precaution in case someone has missed it
What is te 4-1 pre-school booster?
Tetanus, diptheria, whooping cough and polio
What is the 3in1 teenage booster?
Tetanus, diptheria and polio
What is shingles and how does it happen?
Caused by chickenpox virus, remains latent in spinal nerve cells and reactivated (usually when reduced immune system e..g old age)
What is the vaccine for shingles and why is it given?
Since reactivation common in older people due to reduced immune function
2 vaccines - zostavax (live attentuated) and shingrix (recombinant sub-unit)
Recombinant one given to elders
What is neisseria meningitidis? and what does it cause?
Gram -ve bacterium that causes menigitidis and other disease e.g. sepsis
- has multiple sero groups (classifified according to structure of polysaccharide coat)
Do vaccine scehdules saty constant and give an example
No, MenACWY vaccine, now given to teenagers as combination of four serogroups (different before) - schedules change
What are the MenC current vaccination schedules?
HiB/MenC combined vaccine at 1 year - MenC is conjugated bacterial polysaccharide to tetanus toxoid
MenACWY at 14yrs old - polysaccharides for A,C,W,Y serogroups conjugated to diptheria or tentanus toxoid
Why was it difficult to develop vaccine against menB’?
polysaccharides to similari to human cells
What is the current MenB vaccine?
Not made from polysaccharides but from 3 major proteins found on surface of most meningococcal bacteria combined with outer membrane of 1 Men B strain - need adjuvant aluminium hydroxide to make the vaccine strong
What is the HiB vaccine? and what is it used against?
used against H. influenzae - bacterial meningitis
- Type B capsule polysaccharide conjugated to diptheria/tentanus toxoid OR meningococcal outer membrane proteins
What causes diptheria disease?
Diptheria bacteria toxin
Where does diptheria bacteria multiply?
Usually non-invasive multiplication of bacteria in nose, pharnx, nose
How does diptheria toxin cause damaged’?
Toxin produced locally but absorbed by lymphatics and acts at distance causing systemic effects (damages heart, kidney, nerves) and kills epithelial cells forming ulcers and pseudomembrane
What are bacterial toxin disease?
Diseases caused by toxins given off by bacteria
Give a few example of bacteria toxin disease?
Diptheria, tetanus, pertussis
What is the vaccine for diptheria?
combines vaccine - DTaP or dTaP (higher level of toxoid in D)
Diptheria toxin converted to toxoid so not toxic but still immunogenic
- combined with alumnium salts
What is the bacteria that causes tetanus?
Clostridium tetani
What is the mechanism of tentanus disease? + what the bacteria does and symptoms
bacterial toxin disease
tetanus toxin is a neutotoxin that inhibits neurotransmitter release causing voilent spastic paralysis (e.g. lock jaw, permanent smile)
What is the vaccine for tetanus?
Tetanus toxin treated to makde toxoid (not toxic but immunogenic)
combined with aluminium salta
What is the pertussis and the bacteria that causes is?
Whooping cough caused by bordetella pertussis
What is the mechanism of action of whooping cough bacteria?
Bacterium adhered to ciliated epithelial cells in upper resp tract can multiply
Sectrets pertussis toxin causing systemic symptoms including increased luekocytes (rise in white blood cells)
What was the old vaccine for pertussis? and why was it changed
Whole cell killed vaccine - reactogenic (headaches etc..) and concerns of efficacy
What does the new pertussis vaccine have?
Acellular vaccine now (not whole cell)
Pertussis toxoid with filamentous haemogluttinin and pertactin to promote adhesion to cells
- antibodies produced against this blocks adhesion of toxin and neutralises toxin
What is DTaP?
Diptheria, tetanus and acellular pertussis vaccine
- vaccine for all the 3 bacterial toxin diseases
Why is the influenza virus given?
Protect high risk people and reduce circulation of virus
Who gets the influenza virus?
Clinical risk, over 65, carers and health care workers, household contacts of immunocompromised people, pregnant women, children
What are the types of influenza and the most common?
A , B and C
B is most common
What is antigenic drift in influenxa?
mutation and selection in surface proteins
What is antigentic shift in influenza + examples?
gene reassortment betweeen antigenically different strains producing hybrid e.g spanish flue, swine flu
What is in the flu vaccine?
2 subtypes of influenza A and 2 subtypes of influenza B
- changes based on predominant strain of the year
How does vaccine effectiveness of influenza vary?
Age group - doesn’t protect elderly much
Antigenic shift and drift - mismatch of vaccine may reduce effectiveness in future
diff vaccine given to elders - FLUAD - to make it more immunogenic
Which bacteria cause pneumonococcal infection?
Streptococcus penumoniae
What diff conditions can occur in pneumonococcal infection?
Meningitidis Pneumonia Sinusitis INVASIVE PNEUMONOCOCCAL DISEASE etc...
define invasive disease
Bacterium can be isolated from blood or another located that normally is sterile - usually in elderly and young
What is the pneumonococcal vaccine? - 2
Polysaccharide vaccine from 23 serotypes (PPV23)
- under 2 years old need conjugated version
Polysacchardies from 12 most common capsule types conjugated to diptheria toxoid (PCV 13)
What does HPV cause?
genital warts, cervical cancer
What are the risk serotypes of HPV?
serotypes 16 and 18 lead to cervical cancer
6 and 11 not risky - only warts
What are the HPV vaccines?
Subunit vaccines of capsid protein - virus like particles - resembles virus but no genetic material so not infectious
Cervarix against 16 and 18 serotypes
Gardarix - 6, 11, 16 and 18 (protects from genital warts too)
Why is tetanus toxoid vaccine given in pregnancy?
Tetanus toxoid vaccine in late pregnancy to produce IgG - against neonatal tetanus - antibodies transferred to foetus for protection
How does the IgG produced by mother’s due to tetanus vaccination reach foetus?
Antibodies taken up by endocytosis where antibodies binds to receptor due to lower pH than in blood
Once release into foetal blood, higher pH so IgG is released from receptor in circulation
Which vaccines are given to mother during pregnancy? and why
Tetanus, diptheria, pertussis/polio
Flu
Complications = either new born contract disease and dies or pregnant woman with flu develops complications causing still births and premature births
What is the vaccine for tuberculosis (myobacterium tuberculosis)?
not in uk schedule (not routine but still given if needed) but called BCG (Bacillus calmette guerin) - a live attentuated vaccine containing myobacterium bovis)
How do we diagnose TB?
manoux test - inject PPD(purified protein derivative) of tuberculin(extracted from M tuberculosis) into skin
