Vaccines are a precautionary measure used to provide immunity to an infectious disease. Believe it or not but the vaccine itself usually contains elements of the disease or virus. The reason for this is by introducing certain weakened elements of the disease into the body, it is able to recognise the disease and thus has the ability to fight it.
The use of vaccines has been able to effectively stop the widespread of many virus’ such as smallpox and has helped further reduce the spread of diseases
such as measles and polio.
Edward Jenner both invented the concept of and invented the first vaccine. The first vaccine was introduced for the purpose of curing cowpox.
Although vaccines are intended to help fight infections and diseases, this is not always the case. As a vaccine contains some elements of that to which it is trying to fight; sometimes the body is unable to respond and fight even the weakened elements that are contained in the vaccine.
Such an occurrence usually happens when the host’s immune system fails to react correctly.
Another reason why someone may react negatively to a vaccine is due to genetics. Some people do not possess the B cells necessary for the creation of antibodies.