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Science

Antibiotics and drug testing

Some issues with vaccination

Viruses

spherical shaped virus showing a cross-section through the core

A hepatitis C virus showing DNA enclosed in a protein coat.

Some common diseases like influenza (flu) and the common cold are caused by viruses. These mutate quickly, and this changes their surface proteins. This makes it almost impossible to develop a permanent vaccine [Vaccines: substances containing disabled antigens of a particular disease, usually administered via injection. Vaccines stimulate the body to produce antibodies to provide immunity against that disease. ] against them. A new flu vaccine has to be developed every year, after the strain has been analysed.

There is no vaccine for the common cold because the virus that causes it mutates far too quickly. By the time a vaccine could be developed, the virus would have changed its surface proteins and would no longer be recognised by the antibodies [antibodies: Proteins produced by the body's immune system that attack foreign organisms (antigens) that get into the body. ].

Policies

Watch

You may wish to view this BBC News item (2006) about the recommendation that pregnant women should be offered the flu vaccine in winter.

The government has policies on vaccination which advises which stage in their life people should be vaccinated against different diseases. The policies and advice are updated as and when new scientific information becomes available.

Ideas about science - weighing up arguments

With respect to vaccination policies, you need to be able to:

  • Clearly state the issue. For example, is the risk of suffering side-effects from the vaccination greater or less than the risk of catching the disease?
  • Summarise different views that might be held. For example, some people used to think there was a risk of children developing autism when they had the MMR vaccine. Other people thought the MMR vaccine was safe and there was no risk of developing autism.
  • Identify and develop arguments based on the idea that the right decision is the one that leads to the best outcome for the majority of people. For example, even though there may be a slight risk from being vaccinated, society as a whole will benefit because it will help to reduce the risk of the disease being passed on to other people.
  • Identify and develop arguments based on the idea that certain actions are very hard to justify because they are considered unnatural or wrong. For example, most people think governments should not pass laws making vaccination compulsory, because that would take away our human right to freedom of choice.

Epidemics

During an epidemic, an infectious disease such as influenza spreads very quickly. Epidemics can be prevented if a high proportion of the population has been vaccinated. This reduces the number of people who are able to catch the disease and pass it on to others. The more infectious the disease, the higher the proportion of the population that must be vaccinated to prevent the epidemic.

Ideas about science - feasibility

With respect to vaccination policies, you need to be able to distinguish what can be done, ie what is technically feasible, from what should be done. For example, smallpox is the only disease that has been eradicated from the planet by vaccination. This was possible because smallpox is spread by direct contact, and not through the air.

This made it possible to vaccinate enough people in the world to completely stop the disease from spreading.

Some other diseases are more infectious but if we could vaccinate a sufficient number of the world’s population we could, in theory, eliminate the disease. However, at the moment this is not technically feasible because we do not have enough vaccine, some areas of the world are at war and inaccessible, and some people would refuse to be vaccinated.

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