Lesson 3.2 - Vaccines & Vaccination

Question 1

Parts of Chain of Transmission

Answer 1

• Infectious agent
• Reservoirs
• Portal of exit
• Means of transmission
• Portal of entry
• Susceptible host

Question 2

How do vaccines work [simplified]?

Answer 2

• Illicit immune response w/o causing disease to susceptible host
• Stimulate B- & T- memory cell development
• Prepare immune system to produce antibodies

Question 3

Define immunization

Answer 3

Conferring immunity to a cellular pathogen, virus, toxin

Question 4

Vaccination

Answer 4

• Process of conferring immunity to communicable diseases
  
  • IV, intramuscular injection, oral suspension, nasal spray

Question 5

Vaccine

Answer 5

• Provides antigenic stimulus that doesn’t cause disease; induces immunological memory w/o disease
• Latin for cow (Vacca)

Question 6

Edward Jenner (1749-1823)

Answer 6

• Vaccinated individuals with cowpox pus
  
  • Cowpox by Vaccinia virus
  • Smallpox by Variola virus

Question 7

Vaccines introduced 1960-1970s

Answer 7

Polio, MMR

Question 8

Haemophilus influenzae type b (Hib)

Answer 8

• Bacterial meningitis
• Hearing loss / severe permanent neurologic sequelae
• Hemiparalysis, seizure disorders, focal neurologic deficits, hearing/vision loss, impaired cognition

Question 9

Define sequelae

Answer 9

condition which is the consequence of a previous disease / injury

Question 10

[6*] Types of Vaccines

Answer 10

• Attenuated / Hypovirulent Strains (live strains)
• Dead whole cells / inactivated viruses
• Purified antigen subunits from bacterial cell / viral capsid
• Toxoids
• mRNA
• Adenovirus vector

Question 11

Attenuated / Hypovirulent strains (vaccines)

Answer 11

• Grown in tissue culture / eggs for many generations
• Pathogen no longer able to replicate in humans
• Antigens / epitopes persist
• i.e. MMR vaccine

Question 12

Dead whole cells or inactivated viruses (vaccines)

Answer 12

• Heat, formalin, UV radiation, sound waves
• Antigens / epitopes persist

Question 13

Purified antigen subunits from bacterial cell / virus capsid (vaccines)

Answer 13

• Surface antigen by rDNA technology
• Gene for antigen expressed in yeast / bacteria

Question 14

Toxoids (vaccines)

Answer 14

Inactive toxins

Question 15

mRNA (vaccines)

Answer 15

• mRNA within nano-sized lipid bubble; translated to a viral spike protein
• Pfizer & Moderna
  
  • 2 immunizations; 21 days apart
  • Stored in freezer at -80ºC

Question 16

Adenovirus vector (vaccine)

Answer 16

• Disarmed cold virus with SARS-CoV-2 spike protein
• J&J and Oxford-AstraZeneca
  
  • 1 immunization
  • Stored at 2-8°C

Question 17

Ideal vaccines

Answer 17

• 100% safe and effective, lifelong immunity
• Rapidly changing pathogens require frequent immunizations
  
  • Influenza versus measles

Question 18

Allergic reactions and ineligible populations (vaccines)

Answer 18

• Allergic
  
  • Gelatin components or viruses in cultured eggs
• Ineligible
  
  • Newborns, pregnancy, chemotherapy, immunocompromised, severe allergic reactions

Question 19

Vaccines with boosters

Answer 19

• MMR (Measles, Mumps, Rubella)
  
  • 15 months & 4-6 years
• DTaP (Diptheria, Tetanus, Pertussis)
  
  • 10 years

Question 20

Adjuvants

Answer 20

• Bonded to antigens; slow release
• Mineral oil, Al salts
• Provokes inflammation (attracts macrophages)

Question 21

Conjugated vaccines

Answer 21

Weak antigen is covalently attached to strong antigen

Question 22

Primary & Secondary Response

Answer 22

• Primary: 5-7 days
  
  • Memory B- and T- cells produced
• Secondary: 1-2 days
  
  • Memory immune cell response

Question 23

IgA antibodies

Answer 23

Found in mucous, saliva, tears, and breast milks; protects against pathogens

Question 24

IgD antibodies

Answer 24

Part of B-cell receptor; activates basophils & mast cells

Question 25

IgE antibodies

Answer 25

Protects against parasitic worms; responsible for allergic rxns

Question 26

IgG antibodies (vaccine-related)

Answer 26

Secreted by plasma cells in blood; able to cross placenta into fetus

80% of all antibodies

Question 27

IgM antibodies (vaccine-related)

Answer 27

May be attached to B-cell surface / secreted into blood; responsible for early stages of immunity

(B-cell receptor on naive B-cells)

Question 28

Herd / Population/ Community Immunity

Answer 28

• Indirect protection from infectious disease when majority of population is immune either through vaccination or previous infection
• Ineligible individuals protected
  
  • Outbreaks occur when individuals opt out of lifestyle rzns or fear

Question 29

Basic reproductive rate or R-naught (R₀)

Answer 29

• Avg. # of people a single infected person can transmit disease to
• “Spreadability” of disease
  
  • Sars-CoV-2 R₀: 2.3 - 3.1
  • Measles R₀: 14-18

Question 30

Measles (Rubeola) Characteristics

Answer 30

• REFER TO IMAGE
• Enveloped, non-segmented, (-) sense RNA virus
• Rash (immune response), high fever, cough, runny nose, red/watery eyes
• Virus remains active / contagious up to 2 hours

Question 31

Measles Complications

Answer 31

• 1/3 patients suffer complications
  
  • 1/12 diarrhea
  • 1/20 bacterial pneumonia
  • 1-3/1000 encephalitis
  • 1-2/1000 death (increases to 25% in low-income countries)

Question 32

Measles before & after 1963 (Statistics)

Answer 32

• Before
  
  • 3-4 million cases, avg. 450 deaths
  • Epidemic every 2-3 years
  • >50% by 6 y/o, 90% by 15
• After
  
  • 98% cases decreased after vaccine (MMR)
    
    • Lifelong immunity
    • 1990s: fears of discredited claim of causing autism
    • 2000: eradicated, no domestic origin
      
      • Small # from unvaccinated travelers

Question 33

MMR Vaccine (Dosages)

Answer 33

• Attenuated virus unable to grow in human cells generations later
• 1st dose: 12-15 months, 95% effective
• 2nd dose: 4-6 y/o, 99% effective

Question 34

2019 Measles Cases in U.S.

Answer 34

Refer to image.