(a) How does the human body respond when vaccine is introduced into it?

(b) It is said that vaccinations are a must for a healthy society. Justify. [3 Marks]

(a) Vaccines are prepared from attenuated antigens. When a vaccine is introduced into the human body, T cells get activated. T cells stimulate the production of antibodies by the B cells. Antibodies neutralises or destroys the attenuated antigen. The B cells and T cells create a memory about the antigen. When the active antigen infects the body subsequantly, this memory helps the body to activate the B cells to produce antibodies against the antigen faster. [2 Marks]

(b) Vaccinations give immunity against many deadly diseases. This includes tetanus and chicken pox. Children are given these vaccines to protect them against such diseases. Therefore it is necessary for a healthy society. [1 Mark]