Vaccinology - Background of vaccines Flashcards
1
Q
What was the first vaccine?
A
Cowpox live virus against smallpox
2
Q
Which virus causes smallpox?
A
Variola major
3
Q
What is the mortality of smallpox?
A
30%
4
Q
By which means is smallpox transmitted? (2)
A
- Direct contact
- Aerosols
5
Q
To which virus family does the smallpox virus belong?
A
Orthopox
6
Q
What was the first smallpox intervention? When was it invented?
A
Variolation, ~15th century
7
Q
What was the method of smallpox variolation?
A
Intranasal inoculation of dried scabs from patients with mild disease
8
Q
Why does variolation for smallpox cause less disease than natural smallpox infection?
A
Intranasal instead of lower respiratory tract infection
9
Q
What was the case fatality rate of variolation for smallpox?
A
2%
10
Q
For which diseases, in addition to smallpox, was the method of variolation used?
A
- Rinderpest
- Measles
11
Q
Who discovered the possibility of using inonculation with cowpox material to protect individuals against smallpox? When did this take place?
A
Edward Jenner, 1796
12
Q
Which transmission route/sources were used for cowpox material for smallpox vaccination/inoculation? When were each of these methods used?
A
- Arm-to-arm (until mid-19th century)
- Production in cattle (1805 onwards)
- Freeze-dried (1940 onwards)
13
Q
When were bifurcated needles for smallpox vaccination introduced?
A
1961
14
Q
What is the rationale of the use of bifurcated needles in smallpox vaccination?
A
Making scratches in the skin to allow for local cowpox infection
15
Q
What was the case fatality rate of smallpox vaccination?
A
<0,0001%
16
Q
Which conditions make smallpox eradicable? (5)
A
- Limited pathogen variability
- No animal reservoir
- No persistent infections
- Effective vaccine available
- Good diagnostic methods
17
Q
When did the WHO smallpox eradication campaign start?
A
1967
18
Q
When was the last smallpox case?
A
1978
19
Q
When was smallpox declared eradicated?
A
1980
20
Q
What are complications of vaccinia vaccination? (7)
A
- Progressive vaccinia
- Generalized vaccinia
- Contact vaccinia
- Secondary infections
- Post-vaccine encephalitis
- Ezcema vaccinia
- Foetal vaccinia
21
Q
What is contact vaccinia?
A
From inoculated pustule to other parts of the body and/or other individuals
22
Q
What are common secondary infections of a vaccinia vaccination?
A
Herpesviruses
23
Q
When was the last smallpox outbreak in The Netherlands?
A
1952
24
Q
When was vaccinia vaccination stopped in The Netherlands?
A
1971
25
What is the danger of cessation of smallpox vaccination in many countries?
No vaccine-mediated immunity to poxviruses, creating a potential new niche for animal poxviruses
26
Against which situations can vaccines 'protect'? (4)
1. Infection
2. Transmission
3. Disease
4. Death
27
Who discovered vaccine attenuation?
Louis Pasteur
28
How did Louis Pasteur discover vaccine attenuation?
By heat-inactivation of bacteria
29
To which diseases was vaccine attenuation applied by Louis Pasteur & his close colleagues? (4)
1. Anthrax
2. Rabies
3. Tuberculosis
4. Diphtheria
30
To which virus family does polio virus belong?
Enterovirus
31
What is the genome type of poliovirus?
+ssRNA
32
How many serotypes of poliovirus are there?
3
33
Where in the body does poliovirus replicate? (3)
1. Pharynx
2. GI-tract
3. Local lymphatics
34
How does poliovirus reach the CNS?
Haematologic spread
35
What is the effect of polio infection of the CNS?
Viral spread among the nerve fibres, leading to destruction of motor neurons
36
What is an important problem in the detection and prevention of polio outbreaks?
Polio infections are frequently asymptomatic
37
Which two vaccines are available against polio? What kind of vaccine are they?
1. Salk vaccine: inactivated intramuscular
2. Sabin vaccine: live attenuated oral
38
What is the problem with polio eradication?
The high number of asymptomatic cases -> makes it hard to assess whether polio has truly disappeared from the population
39
When was a global eradication campaign for polio started?
1988
40
Which is the only currently persisting natural polio serotype?
Serotype 1
41
What is the cause of most polio cases worldwide?
Vaccine-induced polio
42
How was measles virus attenuated?
Passaging in different human and chicken embryonic cell lines at reduced temperature
43
Vaccine-induced immunity to measles is [worse than/as good as/better than] immunity induced by natural infection
Vaccine-induced immunity = worse than natural infection
44
Does measles meet he criteria to be eradicated?
Yes
45
What is a major safety problem around the administration of vaccines?
Needle accidents
46
What can needle accidents lead to? (2)
1. Transfer of disease
2. Injury
47
What was the estimated yearly incidence of needle accident-induced hepatitis B/C or HIV, prior to the WHO vaccination safety programme?
~2 million cases of hepatitis B/C or HIV per year
48
Why is injection safety still a problem? (3)
1. Lack of knowledge about the danger of injection
2. False belief that injections are more effective than oral medications
3. Monetary incentives for clinicials to use injections
49
Why does false belief that injections are more effective than oral medication cause problems surrounding injection safety?
Over-use of injections
50
What are common practices surrounding injection that harm injection recipients? (5)
1. Keeping freeze-dried vaccine for >6 hours after reconsitution
2. Mixing two partially-used vials of vaccine
3. Storing mediations & vaccines in the same refrigerator
4. Applying pressure to bleeding sites with used material/finger
5. Use of unsterile needles & syringes
51
What are common practices surrounding injection that harm healthcare workers? (4)
1. Re-using needles & syringes
2. Carrying needles/placing them on a surface prior to disposal
3. Re-capping of needles
4. Reaching into a container of used needles/syringes
52
What is the chief solution to reduce injection safety risk?
Education campaigns & training
53
What are common mild adverse effects of vaccine administration? (5)
1. Local redness/swelling
2. Pain
3. Headache
4. Fever
5. Nausea
54
What are common severe adverse effects of vaccine administration? (2)
1. Life-threatening allergic reactions/seizures
2. Systemic disease
55
When was predisposition to enhanced first shown for vaccinations? For which types of vaccines?
1960s, with formalin-inactivated RSV and measles vaccines
56
What is the result of formalin-inactivated (FI) RSV vaccine-induced disease enhancement?
High hospitalization rate during first RSV season after vaccination
57
What are the symptoms of formalin-inactivated (FI) RSV vaccine-induced disease enhancement? (3)
1. Febrile pneumonia
2. Bronchiolitis
3. Pulmonary infiltrates
58
What was the major predictor for severity of disease in formalin-inactivated (FI) RSV vaccine-induced disease enhancement?
Age -> severity of disease is inversely correlated with age
59
What causes younger individuals to have more severe disease in formalin-inactivated (FI) RSV vaccine-induced disease enhancement?
Younger individuals are less likely to have experienced prior RSV exposure -> disease enhancement is more severe when no natural immunity was present before vaccination
60
How does formalin-inactivated (FI) measles virus vaccine-induced disease enhancement manifest?
Atypical measles syndrome developing several years post-vaccination
61
What causes the effects of formalin-inactivated (FI) measles virus-induced disease enhancement to appear much later than those for RSV?
Measles virus is more susceptible for neutralizing antibodies than RSV is -> takes a longer time for immunity to wane enough to allow a measles virus infection
62
What are the symptoms of formalin-inactivated (FI) measles virus vaccine-induced disease enhancement? (3)
1. High fever
2. Petechial rash
3. Pneumonia with cellular infiltrates
63
What is the mechanism of disease enhancement of formalin-inactivated vaccines?
Skewing towards a Th2-response without inducing a CD8+ response ->
This results in a secondary Th2 response with a primary CD8+ response upon infection ->
Rapid accumulation of MV/RSV-specific Th2s in the lung upon infection ->
Th2's cause immune-mediated pneumonia -> allergic-type hypersensitivity response to these viruses
64
Is there an established link between auto-immune disease and vaccination?
Yes
65
For which auto-immune diseases is there an established link to vaccination? (3)
1. Narcolepsy
2. Bell's palsy
3. GBS
66
What is the caveat of the link between GBS and vaccination?
GBS is seen in association with (large) vaccination campaigns, but the incidence of GBS is much higher in natural infections -> vaccination is actually protective of GBS
67
What is an example of an epidemiological risk of vaccination? Explain.
Rubella -> prior to vaccination, (nearly) everyone got infected in their childhood
Now: infections happen at a later age -> can happen in (unvaccinated) pregnant people -> higher risk of congenital rubella syndrome
68
What is the main goal of rubella vaccination?
To protect pregnant people (and not necessarily to protect the infected children)
69
How does rubella manifest during childhood?
Mild disease
70
How does rubella manifest during pregnancy?
Risk of congenital rubella syndrome
