Ch 17 Infectious Diseases and Vaccines

Question 1

Emerging Disease

Answer 1

something new, not previously observed

Question 2

example of an emerging disease

Answer 2

• New strains of influenza

- SARS-CoV-2

Question 3

Re-emerging disease

Answer 3

something old, coming back again

Question 4

example of a re-emerging disease

Answer 4

measles in the US

Question 5

What factors can increase the likelihood of emerging diseases?

Answer 5

• increases in international travel
• mass distribution of contaminated food
• improper antibiotic use
• spread of humans into previously uninhabited areas, introducing to novel microbes

Question 6

What factors can increase the likelihood of re-emerging diseases?

Answer 6

• combinations of diseases (HIV and TB)

- laxity in vaccination program adherence

Question 7

Example of re-emergence combinations of diseases

Answer 7

HIV and TB

• in the 90s, it was thought that TB would soon disappear as a problem in the US
• the AIDS epidemic resulted in a large increase in immunocompromised individuals, who subsequently became sick with Mycobacterium
• regular treatment of immunocompromised patients with antibiotics resulted in resistant TB strains

Question 8

Example of re-emergence of disease due to laxity in vaccination program adherence

Answer 8

• diptheria in Soviet Union
• Whooping cough in US
• Measles in US

Question 9

Passive immunization

Answer 9

delivery of preformed antibody

Question 10

Protective immunity can be achieved by ___ or ____ immunization.

Answer 10

active;passive

Question 11

Conditions that warrant passive immunization

Answer 11

• immune deficiency
• toxin or venom exposure with immediate threat to life
• exposure to pathogens that can cause death faster than an effective immune response can develop

Question 12

Why can passive immunization lead to Type I or III hypersensitivities?

Answer 12

Ab agents are typically made from animals

Question 13

What is the goal of vaccination?

Answer 13

to provide a primary exposure to a safer form of an antigen, either by exposing to a protein/polysaccharide or by exposure to a weakened (attenuated) form of the pathogen

Question 14

The goal of vaccination is to provide a ____ ______ to a safer form of an antigen.

Answer 14

primary exposure

Question 15

Vaccinations provide _____ ______ without the potential negative consequences of a natural infection.

Answer 15

active immunity

Question 16

Side effects of vaccines, when present, are usually indicators of ____ _____ to a novel pathogen

Answer 16

immune reaction

Question 17

Herd immunity

Answer 17

resistance to the spread of an infectious disease within a population that is based on pre-existing immunity of a high proportion of individuals as a result of previous infection or vaccination

Question 18

Basic reproductive number values

Answer 18

the infectibility of a disease

Question 19

Simplified calculation for finding the percentage of people that need active immunity against an agent to achieve herd immunity is based on the:

Answer 19

basic reproduction number (R0) of the agent

Question 20

How do you calculate the approximate level of herd immunity required based on the R0 value?

Answer 20

Herd immunity= 1 - 1/R0

Question 21

Once a vaccine is approved, what other safety measures are in place to ensure that vaccine is still as safe as possible?

Answer 21

after approval by the FDA, every lot of vaccine must be tested before release and manufacturing facilities are checked regularly for compliance of safety and manufacturing procedures

Question 22

Live attenuated vaccine components

Answer 22

pathogens are weakened by continuous growth in conditions outside of their ‘ideal’

Question 23

Pros of live attenuated vaccines

Answer 23

• retain their ability to replicate, promoting both humoral and cell-mediated responses
• often do not need boosters

Question 24

Cons of live attenuated vaccines

Answer 24

• may mutate back (revert) to pathogenic form
• may have more side-effect complications
• may also require a “cold chain” for stability during transport

Question 25

Inactivated vaccine components

Answer 25

heated or chimically treated to inactivate pathogen

Question 26

Pros of inactivated vaccines

Answer 26

• no reversion to pathogenic form

- often more stable/easy to store and transport

Question 27

Cons of inactivated vaccines

Answer 27

• require booster shots
• don’t replicate in host, so often don’t induce cell-mediated immunity well (humoral only)
• possible chemical exposures/adjuvants often required
• potentially dangerous if not all pathogen is killed/inactivated

Question 28

Subunit vaccine components

Answer 28

• use purified macromolecules derived from pathogen
• inactivated exotoxins/toxoids
• inactivated capsular polysaccharides
• inactivated surface glycoproteins (or recombinant protein Ag_

Question 29

Pros/cons of subunit vaccines

Answer 29

similar to those of innactivated vaccines

Question 30

Conjugate/multivalent subunit vaccines

Answer 30

some molecules aren’t strong enough Ags on their won to stimulate a good response

• couple them with something else that is (conjugate)
• deliver them in a mixture of proteins (multivalent)
• have to deliver Ag into cells for presentation in MHC I