4.3.1.7 Vaccination

Question 1

How do vaccines prevent illness in an individual?

Answer 1

• Vaccines introduce small quantities of dead or inactive forms of a pathogen into the body
• white blood cells respond and stimulated to produce antibodies specific to pathogen complementary to the antigens on the pathogens
• if the same pathogen re-enters the body (reinfection) white blood cells release antibodies, with the antibodies being release at a faster rate in larger quantities
• the antibodies destroy + kill the pathogen preventing infection and preventing any symptoms OR antibodies cause pathogens to clump together
• WBCs engulf pathogens by phagocytosis

Question 2

How can vaccines prevent the spread of pathogens?

Answer 2

by immunising a large proportion of the population, the spread of the pathogen is reduced as there are less people to catch the disease from (herd immunity)

Question 3

Advantages of vaccination:

Answer 3

• have eradicated many diseases so far e.g. small box and reduced the occurrence of many e.g. rubbella
• epidemics (lots of cases in an area) can be prevented through herd immunity

Question 4

Disadvantages of vaccination:

Answer 4

• not always effective in providing immunity
• bad reactions (e.g. fevers) can occur in response to vaccines (although very rare)