Edward Jenner• Edward Jenner is an English scientist that lived inthe 18th century.• His works and findings include finding the curefor smallpox and creating a vaccine.• He discovered that milkmaids did not contractsmallpox, however they did contract cowpoxmuch less serious condition.• Jenner concluded that the pus from the blisterson the milkmaids hands, caused bycowpox, prevented the milkmaids fromcontracting smallpox
• He inoculated (infected on purpose) a smallboy, by infecting his arms with the pus from thecowpox, causing the boy to become infected.• After a short fever, the boy returned to normalhealth.• Jenner then realised the boy could not contractsmallpox, or the cowpox virus again.
Immunisation• This is the process in which a person’s bodybecomes resistant to an infection from apathogen.• Passive immunisation is provided by antibodiesfrom outside the body, such as through breastmilk or an injection.• Active immunisation is more common and is theresult of normal infection by a pathogen or by aninjection.
Vaccination• The steps of vaccination are;1. Isolating the weakened version of apathogen, and then infecting an individual withit, normally in the form of an injection.2. The individuals immune response then begins.On the cell wall of the pathogen are antigens.These are often proteins, which white bloodcells recognise as foreign (lymphocytes)3. Lymphocytes then produce antibodies todestroy the pathogens.
• The first time a person is infected by apathogen, the body responds slowly to it, causingthe infected person to be ill for a while. It takestime for the lymphocytes to produce antibodies.• However, if you have had the illness before, andyour memory lymphocytes are able toremember the antigen, they can quickly produceantibodies more quickly, meaning we do not getthe disease for the second time.• This is the case for the cold virus. Each time youget a cold, you do not get the same cold you havehad before, but a slightly different one.
Advantages and disadvantages• There are both risks and advantages associatedwith vaccinations.• An advantage is that they can prevent manypeople from becoming infected by pathogens.• The more people that are vaccinated, the lesslikely it is that anybody will catch the disease, thisis called herd immunity.• A small risk associated is a negative reaction tothe vaccination, causing some people to feel illafter having the vaccine.
• Some people have weakened immune systems(such as people with HIV/AIDS), and have to becareful when receiving a vaccine.• In the past there has been controversysurrounding vaccines, such as the MMR vaccine(measles, mumps and rubella). Some peoplesuggested there was a link between the vaccineand autism, causing the number of children beingvaccinated to go down. It was later discoveredthat there was no link between the two, butsome parents still do not trust the vaccine.
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