Vaccinations are the preparations of a week or killed pathogen in order to prevent the person from contracting a particular disease or infection. They are mostly used as preventative manners however are needed when a person is at risk, or is believed to have contracted the disease. This then helps to greatly improve immunisation (to be protected from the disease or infection) all around the world. This is done by exposing peoples immune system to foreign particles in extremely small amounts. This can be done orally or through an injection, usually in the upper arm.
Once the body has detected the foreign particle
(antigen), then the third line of defence is
Figure 1: Primary and secondary immune responses on initial exposure on initial exposure to an antigen and a second exposure to the same antigen
Source: Chidrawi, Glenda, Margaret Robson, and Stephanie Hollis. "A Search For A Better
Health." Biology in Focus: HSC Course. South
Melbourne, Vic.: Cengage Learning, 2010. 299.
instigated. In this process, the T cells encounter the antigen, begin cloning and producing cytotoxic T cells which are needed to kill the antigen. Working alongside the T cells, are the B cells. They multiply themselves to form plasma cells and produce antibodies which attach to the antigens in order to neutralise them. The primary response is when there is enough antibodies to enable them to destroy all the infected antigens, resulting in the recovery of the host.
Memory T cells are used to guarantee that if the antigen enters the host again, then their response is much quicker than the first. They activate the B cells and cytotoxic T cells and the amount of plasma cells that the B cells produce increase dramatically, which then in turn produce even more antibodies than the first response, as shown in
Figure 1. This is to ensure that the antigens are destroyed before their numbers are too large. Vaccinations, when done not only to the individual but done in a large mass, then this is ‘herd immunity’. This is to ensure that even though there may be some people in a community who are susceptible to a disease, the continued spreading of the the disease is highly unlikely to happen.
The smallpox disease (or Variola Vera) only effects humans and is caused by the variola virus belongs to the genus orthopoxvirus and subfamily
Chordopoxvirinae. There are two classifications of the variola virus, which are the variola minor, and major. Smallpox was transmitted from face-to-face contact with another person, or from the inhalation of saliva - usually from coughing. Although, the virus can live in the infected persons bedding or clothing
Figure 2: The before and after results
for up to a week. In the first 14 days, the virus
of the ‘WHO Intensiﬁed Worldwide
multiplies and continues to develop, however at this
Smallpox Eradication Progress’ until it’s discontinuation in 1976
point the host is not contagious but may experience
symptoms such as fever, headache, and muscular
aches and pains, similar to the common flu. The virus
then creates virions to enable it to move from cell to cell in an effort to spread to infect the skin which causes pustules to form, in the shape of a dome, similar to chicken pox. In the body, cytotoxic T cells are the first to react. They are able to distinguish which of the cells are infected and are able to destroy some of them, yet others are not destroyed and this is when why continue to spread and the person becomes sick with smallpox.
In Australia, with the eradication of smallpox in 1980, the vaccine was also discontinued, showing that the vaccinations instigated by the WHO had been a complete success. The World Health Organisation thought that mass vaccination was not successful, rather it would be better to vaccinate someone showing