Vaccination

Página 1

Two types of

immunity-

·

Passive

immunity is produced by the introduction of antibodies into individuals from an

outside source. As the antibodies are not being produced by the individual

themselves, they are not replaced when they are broken down by the body.

·

Active

immunity is produced by stimulating the production of antibodies by the

individuals own immune system. It is generally long lasting.

Features of

a successful vaccination program-

·

A

suitable vaccine must be economically available in sufficient quantities to

immunise all of the current vulnerable population.

·

There

must be only a few side effects, none of which are life threatening and must

not discourage the population from taking the vaccine.

·

Means

of producing, storing and transporting of the vaccine must be available, up to

date and hygienic.

·

Staff

must be trained to administrate the vaccine properly and at an appropriate

time.

·

It

must be possible to vaccinate, most (all, if possible) of the vulnerable

population. This is best done at one time so that, for a certain period, there

are no individuals in the population with the disease and the transmission of

the pathogen is interrupted. This is known as herd immunity.

Why vaccination does not eliminate a disease-

·

Vaccination

fails to induce immunity in certain individuals. E.g. those with a weak immune

system.

·

Individuals

may develop the disease immediately after the vaccination before their immunity

levels have reached high enough to be immune to it. These individuals also may

infect those without a vaccine.

·

Pathogens

mutate frequently, with leads to a change in antigens so the body fails to

recognise it after the vaccine.

·

Due

to the high number of different types of pathogens it is impossible to create a

suitable vaccine for all of them.

·

Certain

pathogens hide within the body’s immune system either inside cells or living in

out of reach places (e.g. the intestines.)

·

Individuals

can refuse to be vaccinated, due to religious, ethical, social or medical

reasons.

The problems of controlling cholera and tuberculosis by

vaccination-

·

Cholera

is an intestinal disease and therefore not easily reached by the immune system.

Any oral treatment doesn’t have enough time to be effective as it is quickly

flushed out by the intestines due to diarrhoea

·

The

antigens of the cholera pathogen change rapidly (Antigenic Variability), making

it difficult to develop an effective and lasting vaccine.

·

Due

to a mobile population cholera spreads faster, than it can be vaccinated.

·

The

increase in HIV infections means that more people have a weaker immune system

thus making it easier for them to catch TB.

·

Poverty,

wars and political unrest has led to many people living in overcrowded and

unsanitary accommodation allowing for the quick spread of TB.

·

The

proportion of elderly people in the population is increasing meaning that a

higher percentage of the population will have a weaker immune system.

1) The information is relevant because

briefly after the children had received the vaccine they had started showing

symptoms of autism. This is important as it shows that some children who had no

symptoms of autism before, had taken the vaccine and thus started showing the

symptoms of autism. So it would be important to find out whether the two are

linked and what the risk is for the child and how we can decrease the risk.

2) The company could give more money to

a different side of the research or fund a different research who findings

overshadows your findings. Or by giving a lower amount of money keep the

reliability of results a lot lower.

New Page