module 02 section 02 (types of vaccines)

Question 1

explain how the immune reaction to cow pox was able to cross-react and protect people from small pox (3)

Answer 1

• cowpox and smallpox share some surface antigens
• immunization with cow pox induces antibodies against cowpox surface antigens
• cowpox antibodies bind to an neutralize the smallpox virus

Question 2

how do vaccines protect individuals at risk in the population that cannot get vaccinated (pregnant, elderly, immunnocompromised, etc.)?

Answer 2

through herd immunity - prevents the spread of infectious disease

Question 3

what happens when immunization rates fall?

Answer 3

herd immunity is lost and there is a potential increase in the incidence of infection

Question 4

define newly emerging disease

Answer 4

newly identified disease (not previously observed)

Question 5

define re-emerging disease

Answer 5

a previously identified disease coming back again

Question 6

what may re-emerging diseases result from?

Answer 6

• globalization (process by which international relationships develop)
• interactions between people and wildlife

Question 7

list three circumstances that result in the re-emergence of disease

Answer 7

(1) combinations of diseases
(2) improper antibiotic use
(3) laxity in vaccination adherence

Question 8

provide an example of how combinations of diseases can result in re-emergence

Answer 8

patients with HIV are immunocompromised and thus have a much higher chance of developping TB compared to a healthy person

Question 9

provide an example of how improper antibiotic use can result in re-emergence

Answer 9

• antibiotic resistant bacteria are increasingly more prevalent bc of overprescription and misuse
• these bacteria can survive antibiotics, and continue to proliferate (bc natural selection), making the antibiotic ineffective
• e.g. OF re-emerged diseases that are antibiotic resistant MDR TB, MRSA

Question 10

explain how laxity in vaccination adherence can result in re-emergence

Answer 10

when people stop getting vaccinated the amount of immune people decreases and introduction of the pathogen into the population can lead to re-emergence

Question 11

what are the 2 types of immunity?

Answer 11

active: preformed by the hosts own system
passive: assisted by the antibodies of another host

Question 12

define active immunity in detail

Answer 12

induces humoral or cell-mediated immunity and memory following exposure to an antigen

Question 13

what are the 2 types of active immunity?

Answer 13

natural & artificial

Question 14

define natural active immunity

Answer 14

following exposure to an infectious disease, an individual produces antibodies, recovers from the infection, and then has long-term immunity to the antigen

Question 15

define artificial active immunity

Answer 15

• getting immunized (vaccination) generates long lasting immunity
• the individual is usually not infected with the actual disease - develop immunity from the vaccine alone

Question 16

define passive immunity in detail

Answer 16

involves the donation of external antibodies, giving immediate short lived protection to someone following known exposure or to immunosupressed patients

Question 17

what are the 2 types of passive immunity?

Answer 17

natural & artificial

Question 18

define natural passive immunity

Answer 18

the transfer of maternal antibodies across the placenta provides immunity for the fetus

Question 19

define artificial passive immunity

Answer 19

concentrated immunoglobulin fraction is extracted from pooled serum of immune individuals and injected to protect susceptible individuals

Question 20

what are the 6 characteristics of an ideal vaccine?

Answer 20

(1) provide effective and long lasting immunity
(2) be safe and easy to administer with minimal trauma
(3) have no adverse reactions
(4) have no reversion to virulent firms
(5) be stable (e.g. during storage) - instability can reduce safety and efficacy
(6) be available worldwide and inexpensive

Question 21

what are the 4 main types of vaccines?

Answer 21

(1) live attenuated
(2) killed/inactivated
(3) inactivated toxins
(4) subunit

Question 22

what are live attenuated vaccines?

Answer 22

these contain the virus w reduced virulance such that the virus will infect the host cells but won’t cause disease

Question 23

how many ways can a virus be attenuated?

Answer 23

2

Question 24

how does attenuation of the virus occur for live attenuation I vaccines?

Answer 24

• accomplished by infecting an animal cell culture (monkey cells) with human virus
• results in the virus accumulating mutations that diminish its specificity to human cells

Question 25

how does attenuation of the virus occur for live attenuation II vaccines?

Answer 25

accomplished by genetically engineering the virulent gene of the virus by either mutating or deleting it

Question 26

what are examples of live attenuated vaccines?

Answer 26

• sabin (oral polio vaccine)
• MMR
• Varicella
• BCG
• TB

Question 27

what is a pro of live attenuated vaccines?

Answer 27

excellent immune respone - capable of replicating within host cells, commonly inducing a stronger immune response due to the longer interaction btwn immune cells and pathogen

Question 28

what is a con of live attenuated vaccines?

Answer 28

these are less safe compared to inactivated vaccines - these can revert back to the origional more virulent form and cause disease

Question 29

what are killed/inactive vaccines?

Answer 29

• these consist of microorganisms killed by physical or chemical processes such that they cannot cause disease
• although they’re not functional, they still contain the intact antigen that may elict an immune response

Question 30

what are examples of killed/inactive vaccines?

Answer 30

• inactivated polio vaccine

- pertusis vaccine

Question 31

what is a pro of killed/inactive vaccines?

Answer 31

excellent stabilty profile - with no live components, there’s no risk of inducing the disease it prevents

Question 32

what is a con of killed/inactive vaccines?

Answer 32

less strong immune response - this may not always induce an immune response at first dose, and may not be long lived, requiring multiple doses

Question 33

what are inactivated toxin vaccines?

Answer 33

toxins produced by certain bacteria cause disease - for these vaccines, the toxin is chemically altered and rendered harmless so it won’t cause the disease but it may still induce an immune response against the og toxin

Question 34

what are “toxoids”?

Answer 34

another name for the innactivated toxins used in vaccines

Question 35

toxoid vaccines often rely on what? why?

Answer 35

adjuvants - bc they are soluble proteins

Question 36

what are examples of toxoid vaccines?

Answer 36

• tetanus

- diohtheria

Question 37

what is a pro of toxoid vaccines?

Answer 37

excellent stabilty profile - vaccine cannot cause the disease it prevents bc theres no possibility of reverting

Question 38

what is a con of toxoid vaccines?

Answer 38

• not highly immunogenic - most if the toxins are soluble proteins so they require an adjuvant
• may also require several doses

Question 39

what are subunit vaccines?

Answer 39

these consist only of the antigenic components of the pathogen (no live components)

Question 40

what are examples of subunit vaccines? (3 types + examples)

Answer 40

(1) capsules: influenzae, pnemococcus, N. meningiditis
(2) acellular: B. pertussis
(3) recombinant vaccines: hepatitis B

Question 41

what is a pro of subunit vaccines?

Answer 41

excellent stabilty profile - no live components so theres no risk of inducing the disease

Question 42

what is a con of subunit vaccines?

Answer 42

• less strong immune response - must determine which combination of antigenic properties will produce an effective immune response w the correct pathway
• also, may elict response but there’s no guarantee that memory will form for future responses