a) Define the term prophylaxis.
b) Name the four categories of materials used for preparing vaccines. [5 MARKS]

a) 1 Mark
b) 4 Marks

a) The practice of artificially introducing the germs into the body for developing resistance to particular diseases is called prophylaxis and the material introduced into the body is called the vaccine.

b) The four categories of materials used for preparing vaccines are:
(i) Killed germs
(ii) Living weakened germs
(iii) Living fully virulent germs
(iv) Toxoids