Types of Viral Vaccines

Question 1

Heat killed or inactivated Vaccine

Answer 1

• Virus physically treated with heat or irradiation
• Virus chemically treated with formalin
• ie. influenza, Salk polio vaccine, typhoid, cholera, pertussis
• Polio virus transmitted by fecal-oral route
• Only infects humans

Question 2

Live attenuated Vaccine

Answer 2

• Live virus that has been mutated so has reduced ability to grow in humans (passage in
animal cells) and is no longer pathogenic
• More potent than heat killed vaccine at elicitng immunity
• Can revert back to pathogenicity (risk to immunosuppressed)
• Sabin oral polio vaccine (immunity to 3 serotypes), smallpox vaccine, measles, mumps, rubella vaccine (MMR), varicella (chickenpox)

Question 3

Subunit Vaccine

Answer 3

• Vaccine against antigenic surface viral components • ie. Hepatitis A and B vaccines (now recombinant)
• Acellular pertussis (usually part of DTaP)

Question 4

Examples of live

Answer 4

MMR PRVVY
measles
mumpes
rubella
Polio (sabin)
Rabies
VZV
Vaccinia 
Yellow Fever

influenza intranasal

Question 5

Examples of Killed

Answer 5

Typhus fever (Ricketsia prowazekii)
Cholera(Vibrio cholerae)
Plague(Yersinia pestis)
Polio (Salk)

Always RIP

Influenza

Question 6

Capsular polysaccharide vaccine

Answer 6

• Vaccine that uses the polysaccharide found in the capsule of the bacteria, as an immunogen
• Bacteria with polysaccharide capsule: Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis
• Provoke T independent response
• Poorly immunogenic in infants < 2 years
• Children under 2 don’t develop a good T independent response
• Does not induce mucosal immunity
• Does not induce IgG response or lasting memory
• Does not generate memory T cells
• Polysaccharides are not processed for presentation to TH cells so do not induce class switching, affinity matura5on, or generate memory T cells

Question 7

Conjugate Vaccine

Answer 7

• Polysaccharide covalently coupled to a carrier protein so as to
convert it to a T dependent an5tien
• Carrier protein stimulates CD4 TH cell response
• Tetanus or diptheria toxoid frequently used as carriers
• Available for Haemophilus influenza type B (HiB) and Neisseria meningitidis
• HEPTAVALENT vaccine for Streptococcus pneumoniae (Prevnar) contains polysaccharides of seven pneumococcal strains linked to diptheria toxoid as carrier

Question 8

Recombinant Vaccines

Answer 8

• Recombinant viral proteins used for vaccines
• Hepatitis B surface antigen
• Human Papilloma viral surface proteins (Gardasil and Cervarix)