vaccination

Question 1

What is passive immunity

Answer 1

Short term immunity from the i toduction of antibodies form another person

Question 2

What is active immunity

Answer 2

Stimulating the production of antibodies by the individuals own immune system

Question 3

What is natural active immunity

Answer 3

Becoming infected by a disease under normal circumstances

Question 4

What is artificial active immunity

Answer 4

Is the basis of a vaccination

Question 5

What are features of a successful vaccination program

Answer 5

Must economically sufficient
• There must be few side-effects, if any, from vaccination. Unpleasant side-effects may discourage individuals in the population from being vaccinated.
• Means of producing, storing and transporting the vaccine must be available. This usually involves technologically advanced equipment, hygienic conditions and refrigerated transport.
• There must be the means of administering the vaccine properly at the appropriate time. This involves training staff with appropriate skills at different centres throughout the population.
• It must be possible to vaccinate the vast majority of the vulnerable population to produce herd immunity.

Question 6

What is herd immunity

Answer 6

resistance to the spread of an infectious disease within a population that is based on pre-existing immunity of a high proportion of individuals as a result of previous infection or vaccination.

Question 7

Why vaccination may not eliminate disease

Answer 7

• Vaccination fails to induce immunity in certain individuals, for example people with defective immune systems.
• Individuals may develop the disease immediately after vaccination but before their immunity levels are high enough to prevent it.
These individuals may harbour the pathogen and reinfect others.
• The pathogen may mutate frequently, so that its antigens change suddenly rather than gradually. This means that vaccines suddenly become ineffective because the new antigens on the pathogen are no longer recognised by the immune system. As a result the immune system does not produce the antibodies to destroy the pathogen. This antigenic variability happens with the influenza virus, which changes its antigens frequently. Immunity is therefore short-lived and individuals may develop repeated bouts of influenza during their lifetime.
•There may be so many varieties of a particular pathogen that it is almost impossible to develop a vaccine that is effective against them all. For example, there are over 100 varieties of the common cold virus and new ones are constantly evolving.
Certain pathogens ‘hide’ from the body’s immune system, either by concealing themselves inside cells, or by living in places out of reach, such as within the intestines, for example, the cholera pathogen.
• Individuals may have objections to vaccination for religious, ethical or medical reasons. For example, unfounded concerns over the measles, mumps and rubella (MMR) triple vaccine has led a number of parents to opt for separate vaccinations for their children, or to avoid vaccination altogether.