Vaccines

Question 1

What are Vaccines?

Answer 1

• Work to prime the immune system by stimulating primary immune responses
  
  • Should not causes disease
  • Desired goal is the production of memory cells that can be activated if ever the pathogenic material is encountered at a later time
  • Vaccines are especially beneficial to protect against viral infections
    
    • Virus cannot be eliminated with chemotherapy
      
      • Prevention makes the most sense
• Some vaccines have greater risk factors than others

Question 2

What are the vaccines categories?

Answer 2

• Live attenuated vaccines
• Whole agent inactivated vaccines
• Subunit vaccines
• Toxoid vaccines
• Conjugated vaccines

Question 3

Live attenuated vaccines

Answer 3

• Consists of pathogen that has been weakened
  
  • Usually accomplished by introducing a key mutation
  • Still maintains many of the properties of the wild-type pathogen
    
    • Ex) virus can still adsorb and penetrate but cannot replicate
  • Stimulates both antibody and cell mediated immunity
  • Can spontaneously mutate back to the wild-type
    
    • Potential to cause disease that you are trying to prevent
  • Examples include: Sabin vaccine against Poliovirus, Rotavirus vaccine, MMRV vaccine (Measles, Mumps, Rubella, Varicella), some Rabies vaccines, vaccine against Mycobacterium tuberculosis

Question 4

Whole agent inactivated vaccines

Answer 4

• Include inactivated virus
  
  • Incapable of adsorption or penetration
  • No risk of causing disease
• Only stimulates antibody mediated immunity
• Examples include: Hepatitis B vaccination, the flu
  shot, Rabies vaccine used in humans, Salk vaccine
  for Poliovirus

Question 5

Subunit vaccines

Answer 5

• Include purified proteins (antigen) taken from pathogenic bacteria and
  virus
• Does not contain any infectious material
  
  • Very safe
• Only stimulates antibody mediated immunity
• Examples include: Hepatitis A vaccination, Human Papilloma Virus Vaccine,
  pneumoshot (contains purified capsule from Streptococcus pneumoniae),
  meningococcal vaccine (contains purified capsule from Neisseria
  meningitidis)

Question 6

Toxoid vaccines

Answer 6

• Consist of bacterial toxins that have been modified
• Maintain the same antigenic properties of the actual toxin
  
  • Toxoid is incapable of causing the same effects as the toxin
    
    • Very safe
• Only stimulate antibody mediated immunity
• Often provide short-lived protection
  
  • Booster shots needed
• Examples include: DTaP vaccine against diptheria toxin, tetanus toxin,
  and pertussis toxin

Question 7

Conjugated vaccines

Answer 7

• Consists of antigen that have been conjugated together
  
  • Increases the overall size of the antigen
  • Addresses limitations of naïve adaptive immune system in children
  • Increased immunogenicity = better protection
  • Examples include: polysaccharide vaccine against capsule of Haemophilus influenzae conjugated to protein