Unit 4 - Active Immunisation and Vaccinations Flashcards
Explain the Placebo effect…
A placebo is a fake treatments that looks exactly like the real treatment, but instead of containing the ingredient meant for the treatment it contains glucose. However, patients do not know they have been given placebo, so since they think it’s the real thing they can sometimes believe they are getting better. This is used to compare data in clinical trials.
Explain Randomisation in clinical trials…
This is when the patients are randomised into each group. This helps eliminate bias because the research team can’t decide who goes where, thus increasing reliability.
What is a Double-Blind Trial during a clinical trial?
This is when not just the patients, but the doctors administering the treatment do not know whether the treatment is real or a placebo. This makes sure doctors cannot influence you, eliminating bias and making the results more realistic and reliable.
What is a clinical trial?
It is a type of medical research. It is the process a new treatment has to go through to see if the treatment is safe, effective and how it effects the user. During the process the research team tests the treatment on volunteers with the illness to see if it works. If the results are good enough the treatment can go on to be verified.
Name the types of vaccines…
- Inactivated pathogen toxins (Tetanus and Diphtheria)
- Dead pathogens (Polio and Hepatitis A)
- Parts of pathogens (HPV and Hepatitis B)
- Weakened pathogens (Measles, Mumps ps and Rubella)
Explain Experimental Error…
Experimental error makes sure that the two groups are as similar to the original group as possible. This means if there was a larger number of older women in the original group, it would be reflected on the two smaller groups. This helps eliminate statistic differences between the groups.
What happens during the three stages of a Clinical trial?
In stage one, the treatment is tested on a small group of people (25-50) to see if it’s safe. In the stage two, the treatment is tested on a larger group of people (150-300) to see if it’s safe, effective and to find out the optimum dose. The 3rd stage is when the treatment is tested on a large group (1000-2000) under a randomised, placebo controlled, double-blind protocol.
What is herd immunity?
It is when a small number of the public has not been immunised however they are still protected as the majority have been immunised, thus preventing spread either to the non-immune individuals or from them because the chance of them meeting an infected individual is very low. This only works when a certain number of people have been vaccinated.
What is a Herd Immunity threshold?
It is the percentage of the population which are immune at which herd immunity against that disease works effectively. The value can vary depending on the vaccine efficacy, the pathogen virulence, and the populations contact parameters (The populations density).
What is Antigenic variation?
When a pathogen is able to change its surface antigens, allowing it to avoid the body’s immunological memory (The body’s memory cells). This prevents eradication of the pathogen as a vaccine cannot be developed to stop it as it is continually changing its antigens. Viruses and some Protozoa have this ability.
Name some diseases which are able to change their antigens…
The Influenza virus (Which is the most notorious), Malaria and Trypanosomiasis.
Give some examples of direct attacks on the immune system…
Tuberculosis is a bacteria which can survive in phagocytes. They stop lysosymes from fusing with the vesicle, thus going infecting I the phagocyte. HIV attacks lymphocytes directly, using them for reproduction, and releases new viral particles which destroy lymphocytes. Antibodies are ineffective against these viral particles.
