35 Protecting the host: vaccination Flashcards

1
Q

Vaccination aims to prime adaptive immune system, so second contact will provide a rapid and effective secondary immune response by memory T and B cells.

What are different types of vaccines and examples?

A

Live attenuated -
- viral - measles, mumps, rubella, vaccinia, varicella, yellow fever, zoster, oral polio, intranasal influenza, rotavirus

  • bacterial - BCG, oral typhoid

Inactivated -
- Whole virus - polio, influenza, hepatitis A, rabies, JE

  • Whole bacteria - pertussis, cholera, typhoid

Fractions -
- toxoids - diptheria, tetanus

  • protein subunits - hepatitis B, influenza, pertussis, HPV 6/11/ 16/ 18
  • polysaccharides - pneumococcal, meningococcal, salmonella typhi, Hib
  • conjugates - pneumococcal, meningococcal, Hib
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2
Q

Who should not be given live vaccines?

A

HIV patients

Pregnant

Inactivated vaccines are safe to use

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3
Q

Why are toxoid vaccines used for diptheria/ tetanus?

A

It is the toxin which is damaging to host, not the bacteria itself. So use inactivated toxoid as vaccine

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4
Q

Inactivated/ protein/ polysaccharide require multiple doses for vaccination. Why is this?

A

Less immunogenic than vaccines with whole organisms.

Sometimes adjuvants are required to improve immune response through inducing activation of Toll-like receptors on dendritic cells to improve antigen presentation. Certain chemicals can be used as adjuvants, such as aluminium salts, and cytokines IL1, IL2, IFNgamma can help boost immune response

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5
Q

What are problems with vaccine safety?

A

Live attenuated -

  • insufficient attenuation
  • reversion to wild type
  • admisiter to immunodeficient patient
  • contamination other viruses
  • foetal damage

Non-living vaccines

  • contamination by chemicals
  • allergic reaction
  • auto-immunity
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6
Q

Why are childrens vaccinations required to be repeated?

A

Can have maternal antibodies, so do not develop own memory cells

Some vaccines are less immunogenic

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7
Q

What are the two types of polio vaccine?

Three serotypes of polio, vaccine works against all three - trivalent.

But polio-2 and polio-3 has been eliminated, so may only need to use monovalent vaccine in future

A

Inactivated IPV - Salk 1954
Injectible
Risk if inadequatley killed

Attenuated OPV - Sabin 1957
Oral - easy to administer
Benefits - replicates in intestine produce local immunity IgA, and can be spread to other household members.
Risk of vaccine associated paralytic polio (VAPP)

they both target polio virus 1/ 2/ 3

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8
Q

What are risks of oral polio vaccine? OPV

A

Can can vaccine associated paralytic polio (VAPP)

OPV virus can be transmitted in community termed circulating vaccine-derived polio viruses cVDPV. If susceptible population, can survive moving between hosts. Mutations slowly develop, and cause paralysis

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9
Q

Why was it difficult to create pneumococcal vaccine?

A

over 90 serotypes

Most common 23 serotypes included in vaccine

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10
Q

Why does haemophilus vaccine target type b serotype?

A

six capsular serotypes, but type b causes 95% of disease.

Usually those under 5 affected

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11
Q

Why is influenza vaccine difficult to develop?

Influenza vaccine contains three flu strains -
2 A strains
1 B strain

A

Antigenic drift - gradual mutation

Antigenic shift - reshuffle of RNA can produce different H/N antigens

Given to people >65 who have weaker immune systems, so may not generate sufficient immune response - immunosenescence

Winter 2020-21
H1N1
H3N2
B

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12
Q

Why is it difficult to produce HIV vaccine?

A

gp120 can mutate easily

killed virus not sufficiently immunogenic

route of infection via genital tract, means need localised mucosal immunity, which vaccine can’t provide

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13
Q

Adenoviruses are useful as vaccine vectors, why is this?

What are draw backs?

A

Induce good CD8 T cell response

Some people have already been infected with adenovirus species, and have antibodies to them, so may not generate good immune response

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14
Q

Why was smallpox easy to erradiacte?

A

highly effective vaccine
Easy to administer vaccine
Single vaccine dose

Infected patients can be easily spotted
Easy to contain patients once diagnosed

Permanent immunity after disease/ vaccination

No animal reservoir

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15
Q

When targeting next disease for erradication, what factors must be present?

A

Humans must be critical to circulating organism - no animal reservoir

Sensitive/ specific diagnostic tools

Effective vaccine

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16
Q

Why is there a problem with developing a dengue vaccine?

A

Antibody dependent enhancement between serotypes

Antibodies generated during primary infection with one serotype of virus will not be sufficient to neutralise a second serotype.

However, they might be able to opsonise the secondary virus, and target it for phagocytes. This can lead to dengue haemorrhagic fever or severe dengue on repeat infection

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17
Q

How are organisms inactivated for vaccination?

A

heat

Chemicals

radiation

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18
Q

some patients have egg allergy. Which vaccine should you seek alternative?

4CMenB
DTaP/ PIV/ Hib
Influenza
MMR
Q fever
Rotavirus
Yellow fever
Rabies
A

Influenza uses embryonated eggs - can use intranasal vaccine instead.

Yellow fever contains eggs and should be avoided

Rabies uses egg embyros and should be avoided

Q fever uses egg embryos and should be avoided

MMR produced in eggs, but is safe as long as no anaphylaxis, as no egg free alternative available

discuss with immunologist if require to give vaccination

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19
Q

VZV susceptible healthcare worker on oncology ward receives varicella vaccine dose through occupational health. She presents two weeks later with vesicular rash. Otherwise well. Not pregnant.

What is next management?

A

Avoid patient contact until lesions crusted over

<5% develop vesicular rash 5-26 days after vaccination. Given her rash is after two weeks, then it is less likely to be caused by vaccine, and may be new VZV infection.

In any case, vaccine strain is sensitive to aciclovir

  • viral PCR of lesion
  • viral genome analysis, to see if wild type. Serology does not help differentiate the two
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20
Q

Which vaccines are live attenuated?

A

Live attenuated -
- viral - measles, mumps, rubella, vaccinia, varicella, yellow fever, zoster, oral polio, intranasal influenza, rotavirus

  • bacterial - BCG, oral typhoid
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21
Q

Which vaccines come as combinantions?

A

MMR
DTaP/IPV/Hib/HepB or DTaP/ IPV/ Hib
Td/ IPV (tetanus)
Influenza A and B

22
Q

What are advantages of combination vaccines?

A

Less uncomfortable for patient

Mor efficient vaccination as easier to administer

Higher vaccine uptake

23
Q

If child has no vaccination history e.g refugee, should they be vaccinated?

A

Vaccinate as if never had a vaccine

Risk of extra dose is minimal if already vaccinated, and far outways risk of disease

24
Q

Fully vaccinated pregnant female, what extra booster should be given between 16-32 weeks?

A

DTaP/ IPV
Inactivated

Studied following outbreak of pertussis in infants

Never give live vaccines in pregnancy, including MMR

25
One year old girl on high dose steroids for nephrotic syndrome for more than one month. Which vaccine contraindicated? ``` DTaP/ IPV/ Hib MenB Inactivated influenza MMR Pneumococcal ```
MMR live vaccine Consider those on 40mg prednisolone or above, for more than a week, to be immunosuppressed. This lasts until 3 months after cessation of immunosuppressive drug
26
Vaccine schedule 8 weeks old If start vaccination before this, poor immune response as will have maternal antibodies. Personal Child Health Record (Red Book) records vaccines
DTaP/IPV/Hib/HepB - injection Meningococcal B (MenB) - injection Rotavirus - oral
27
Vaccine schedule 12 weeks old
DTaP/IPV/Hib/HepB - injection PCV13 - injection Rotavirus - oral
28
Vaccine schedule 16 weeks old
DTaP/IPV/Hib/HepB - injection Meningococcal B (MenB) - injection
29
Vaccine schedule Prior to age of 1 year old, what vaccinations should have been given?
DTaP/IPV/Hib/HepB - 3x doses PCV13 - 1x dose MenB - 2x doses Rotavirus - 1x dose
30
Vaccine schedule 1 year old
Hib/MenC - injection MenB - injection PCV13 - injection MMR - injection
31
Vaccine schedule What should child receive by age 2?
DTaP/IPV/Hib/HepB - 3x doses PCV13 - 2x dose MenB - 2x doses Rotavirus - 1x dose Hib/ Men C - 1x dose MMR - 1x dose
32
Vaccine schedule 3-4 year old
LAIV - intranasal dTaP/IPV - injection MMR - injection
33
Vaccine schedule 12-13 years old 14 years old
HPV - 2x injections 6 months apart. Note - females and males eligible up to age 25. Give three doses if course started after age 15 Td/IPV - injection MenACWY - injection
34
Vaccine schedule What should be given before leaving school?
dTaP/IPV - 5x doses total MenACWY - 1x dose MMR - 2x doses HPV - 2x doses
35
What is in vaccination schedule for elderly?
65 - pneumococcal single dose/ influenza annual 70 - shingles
36
At what age should premature infants be vaccinated?
Vaccinate as with chronological age i.e when they were born This is because even higher risk of childhood disease
37
Inactivated vaccines - how many can be given together? How long to wait between doses?
Can give as many as possible Wait 4 weeks before given another dose of same vaccine is recommended. Some give better response at 8 weeks. If going travelling, or disease outbreak, and rapid immunisation required, can give vaccines early (by one week). However, this often leads to ineffective response, and another dose may be required
38
Can these vaccines be given same day? Yellow fever + MMR Varicella + MMR
Yellow fever + MMR - both live. Wait 4 weeks between Varicella + MMR - both live, can give together. But if not given together, wait 4 weeks before given the second one. Study showed outbreak varicella if given too close together. MMR may attenuate response to varicella
39
Can these vaccines be given on same day? All live ``` BCG rotavirus LAIV oral typhoid vaccine yellow fever varicella zoster MMR ```
Yes, apart from: Yellow fever and MMR - wait 4 weeks between Varicella + MMR - only if given together. If not, wait 4 weeks
40
Household contacts of immunocompromised individual are eligible to receive vaccination, including varicella and seasonal influenza. What precautions should be taken?
Give inactivated influenza vaccine instead of live vaccine, as risk of spreading to household member
41
When is vaccination recommended in HIV patients?
Guided by CD4 count - chapter 6 Green book Avoid BCG at any CD4 count
42
Splenectomy patients are at risk of infection by encapsulated organisms. What vaccines should they receive?
Pneumococcal Hib MenACWY Influenza - annual
43
HBV vaccine introduced in 2017 childhood immunisation schedule. Which other adult groups should receive this vaccine?
HCW Prison staff IVDU Contacts of patient with HBV Babies born to mothers with chronic HBV Haemophiliac CKD Liver diseases
44
What is the advice about avoiding school with following conditions? Chickenpox Herpes simplex Rubella Hand, foot and mouth In all cases, if one child affected then do not need to contact public health. If multiple cases/ outbreak, then inform public health
Chickenpox - until all vesicles have crusted over HSV - none. Avoid kissing and contact with the sores. Cold sores are generally mild and self-limiting Rubella - four days from onset of rash Hand, foot and mouth - none
45
What is the advice about returning to school with following conditions? Impetigo Measles Molluscum contagiosum Roseola
Impetigo - until lesions are crusted and healed, or 48 hours after commencing antibiotic treatment Antibiotic treatment speeds healing and reduces the infectious period Measles - 4 days from onset of rash Molluscum contagiosum - none A self-limiting condition. Unless doing contact sports/ swimming - need to cover lesions Roseola (infantum) - none
46
What is the advice about returning to school with following conditions? Scabies Scarlet fever Slapped cheek (fifth disease or parvovirus B19)
Scabies - return after first treatment Scarlet fever - teturn 24 hours after commencing appropriate antibiotic treatment Slapped cheek - none
47
What is the advice about returning to school with following conditions? Diarrhoeal disease including E.coli, salmonella, shigella, cryptosporidium
Return 48 hours after last episode of diarrhoea/ vomiting
48
What is the advice about returning to school with following conditions? Influenza TB Whooping cough
Influenza - once recovered TB - individualised approach Whooping cough - 48 hours after starting treatment, or 21 days after symptoms started
49
What is the advice about returning to school with following conditions? Mumps Meningitis - bacterial Glandular fever HAV
Mumps - exclude for 5 days after onset swelling Meningitis - bacterial - until recovered Glandular fever - none HAV - exclude until 7 days after onset of jaundice
50
What is difference between eradication and elimination of disease?
Erradication - eliminated worldwide Elimination - reduced to zero (or small number) of cases in defined geographical area
51
Which diseases have been erradicated?
Smallpox - erradicated 1980 Rinderpest - cattle plague erradiacted 2001