BIOL 437 Week 12 (Vaccinations)

Question 1

discovery of 1st vaccine

Answer 1

Smallpox
>virola major (very virulent)
>virola minor
*cross-protective immunity

Question 2

variolation

Answer 2

• inoculating skin of healthy children with dry pustules from mild smallpox cases
• did not always produce immunity
• sometimes caused full-blown smallpox and death of patient
• chain of transmission: new and virulent cases in susceptible people

Question 3

Edward Jenner

Answer 3

-observed milkmaids were immune to smallpox
-vaccine for smallpox produced from cowpox virus
>less side effects than viriolation
>no collateral infections
*small pox is the only human pathogen eradicated by vaccination

Question 4

incdience of infection for common infections

Answer 4

• has declined by more than 95% since vaccinations were introduced
• eradication of small pox
• whooping cough decreased 96%
• measeles, mumps, rubella decreased by 99%

Question 5

global impact of vaccination

Answer 5

• not everyone will gain immunity

- one vaccine can protect more than one person (‘herd immunity’)

Question 6

why was smallpox a good choice for testing intervention efforts?

Answer 6

-survivors were resistant to re-infection even years later
-exposure to small amounts of material from skin postule gave some protection to previously susceptible people
>’prime’ the immune system by exposing a person to a small amount

Question 7

2 most common types of vaccines

Answer 7

1. Live, attenuated

2. Inactivated

Question 8

live, attenuated vaccine

Answer 8

• mimic infection without causing disease

ex. measles, mumps, yellow fever, covid-19

Question 9

inactivated vaccines

Answer 9

• less effective
• no risk of symptoms
  ex. hepatitis A

Question 10

subunit vaccines

Answer 10

• only use part of target pathogen to provoke a response

eg. hepatitus B

Question 11

activation of immune system via vaccination

Answer 11

• results in the generation of Abs and memory B-cells

- acquired immunity: process of Ab production via vaccination

Question 12

toxiod vaccine

Answer 12

• toxin produced by the bacteria

- inactivate the toxin

Question 13

conjugate vaccine

Answer 13

• similar to recombinant vaccines
• combo of two different components
• made using pieces from coats of bacteria

Question 14

valence vaccine

Answer 14

• monovalent: immunize against a single antigen

- polyvalent: immunize against 2 or more strains of same microorganism

Question 15

heterotypic vaccine

Answer 15

• ‘jennerian vaccines’

- pathogens of other animals that do not cause disease or mild disease

Question 16

mRNA vaccine

Answer 16

• novel type

- composed of nucleic acid RNA packed within a vector such as lipid nanoparticles

Question 17

herd/community immunity

Answer 17

• resistance a group of individuals have to a specific disease because of a larger proportion of the group are immune
• can acheive effective proportion without needing the whole population vaccinated

Question 18

immunization by natural exposure or vaccine

Answer 18

• will directly protect individuals from re-infection

- also indirectly protects everyone that they otherwiese would have infected

Question 19

herd immunity refers to

Answer 19

-immunizing only a percentage of all births to prevent an infection becoming an epidemic in a population

Question 20

percentage is related to Ro

Answer 20

-as Ro increases the percentage of population that need to vaccinated to guarantee herd immunity also increases

Question 21

herd immunity threshold

Answer 21

• percentage that must be immunized not just vaccinated
• even if threshold is not actually achieved, having a high percentage of individuals immunized will have indirect benefits for a population

Question 22

if population stays below herd immunity threshold

Answer 22

-then proportion of susceptibiles increases which increases the potential for outbreaks
>absence of infection does not equate to absence of subsequent risk of outbreaks

Question 23

conditions necessary to achieve herd immunity

Answer 23

• pathogen must be restricted to a single host species
• transmission must be relatively direct from one member of host species to another member
• infections must cause solid immunity

Question 24

herd immunity operates well when

Answer 24

• probabiliity of infected individual contacting every other individual in population is the same
• populations are constantly mixing

Question 25

why would vaccine supply be limited?

Answer 25

• logistics
• economics
• severe problem in pandemics

Question 26

targeted vaccinations

Answer 26

• which set of ‘nodes’ get the maximum impact in reducing the spread of disease
• protects entire network with only a few doses

Question 27

vaccine refusal

Answer 27

-emotional topic
-false sense of security becuase many disease are rare today
>they are rare because of vaccines

Question 28

consequences of control

Answer 28

• changes the overal force of infection

- as force of infection decreases, average age at which a person becomes infected increases

Question 29

vaccine ethics

Answer 29

-WHO has guidelines for ethical considerations for vaccine programs in acute emergencies

Question 30

measles and immune amnesia

Answer 30

-temporary immunolgical amnesia due to immune-mediated clearance of measles
>leaves individuals susceptible to opportunistic infectious agents that would normally be controlled by immune system