Vaccines

Question 1

Describe different types of vaccines. Include live attenuated, inactivated, sub-unit, vectored and DNA vaccines. Give examples.

Answer 1

• Live attenuated: defective or weakened form of
  the virus. Ex: measles, oral typhoid.
• Inactivated: organisms are killed or inactivated by heat,
  chemicals and radiation but remain antigenic. Ex: polio, hepatitis A.
• Subunit: seek to stimulate antibodies to HIV by
  mimicking proteins on the surface of HIV.
• Vectored: incorporate harmless bits of HIV
  into established vaccines. Ex: MVA
• DNA: involve HIV genetic sequences, inducing expression of HIV antigens.

Question 2

What are adjuvants? Give examples.

Answer 2

a substance that enhances the body’s immune response to an antigen; innate immune system.
Examples: Alum, MF59, virosomes, AS04.

Question 3

Describe the benefits of using
adjuvants in vaccines?

Answer 3

• increase the response to an vaccine.
• increase seroconversion rates, with reduced responsiveness because of age, disease, or therapeutic interventions.
• regulate the use of smaller doses of antigen.
• fewer doses of vaccine.

Question 4

Describe scheme of immunization (primary and booster).

Answer 4

Primary: one dose and mutliple dose vaccines.
Booster: to maintain immunity level after it declines after some time has elapsed.

Question 5

Give examples of one dose and multiple dose vaccines.

Answer 5

One dose: measles, bumps, rubella.
Multiple dose: polio, DPT, hepatitis B.

Question 6

What is herd immunity?

Answer 6

Immunization of large portions of the population to
protect the unvaccinated, immunocompromised, and immunologically naive.

Question 7

How herd immunity protects the unvaccinated?

Answer 7

Vaccination of the potential carriers within the
population can promote disease prevention in the
unvaccinated.

Question 8

Describe active and passive immunity.

Answer 8

Active Immunity: immunity that is the result of a production of antibodies by the immune system in response to the presence of an antigen.

Passive Immunity: Immunity conferred by an antibody produced in another host. It may be acquired naturally or artificially.

Question 9

List ideal characteristics of a vaccine.

Answer 9

• Excellent safety profile
• Single dose administration
• Offers protection for a long time
• Low cost
• Stability and ease of administration
• Works against a wide range of different strains