ANSWERS

1. What is the difference between a live vaccine and an inactivated vaccine?
   A live vaccine consists of non-pathogenic living organisms of a slightly different strain from the disease-causing organisms, whereas an inactivated vaccine contains antigens. The former stimulates a protective immune response, whilst the latter prevents multiplication of the disease-causing organism.
2. Give 1 advantage of live vaccines over inactivated vaccines.
   Live vaccines are longer lasting than inactivated vaccines.
3. Give 1 advantage of inactivated vaccines over live vaccines.
   Inactivated vaccines are safer, more stable and therefore easier to use.
4. What is a toxoid?
   A toxoid is a form of inactivated vaccine produced from heat-treated toxins extracted from disease-causing organisms. These contain adjuvants such as aluminium hydroxide which help to enhance the immune response to antigens.
5. What is an autogenous vaccine?
   An autogenous vaccine is prepared from material collected from the animal to which the vaccine is to be administered. Autogenous means generated within the body and not acquired from external sources.
6. How does a vaccine work?
   Vaccines mimic natural infections as closely as possible without producing pathological signs. This stimulates the immune system thus giving protection.
7. What is passive immunity?
   Passive immunity is that derived from maternal immunoglobulins in cholostrum or from an injection of antibodies or antiserum.
8. What is active immunity?
   Active immunity is that derived from either the body's natural response to antigens from infectious diseases or an artificial response to toxins or toxoids