How do vaccines work?

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Vaccines are big news right now as a result of the global pandemic. Have you ever wondered how they work, especially now as so many people are getting vaccinated? If you’re curious about the science behind vaccines, then read on.

Traditionally, vaccines worked by introducing a tiny amount of deactivated pathogen into your body. Your immune system then kicks into action and produces antibodies against the antigen. Should your body ever encounter this pathogen again, it will recognise it and know how to fight it off. This is the science behind how many millions of people have been saved from terrible diseases like polio and smallpox, for example.

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A vaccine is designed to prevent a person from contracting a disease, not as a treatment after a person has contracted an illness. Vaccines work hand in hand with the natural activity of the immune system by introducing a virus or bacteria in a small safe dose so that your body can produce a natural immune response and create antibodies. Vaccines require trials before public use. For details on Paid Research Studies, visit trials4us.

The ultimate goal of a successful vaccination campaign is herd immunity. Not only do vaccines help an individual but they have a role in protecting whole communities, including those who are not immunised. This is because there is such a low prevalence of disease that there is minimal opportunity for an outbreak. The bacteria or virus is unable to find enough eligible hosts to survive and will hopefully die off. Real life studies of the Gambia revealed that just 70% of the population being vaccinated was enough to eliminate Hib disease completely.

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There are several different types of vaccines:

Live Attenuated – A weak version of an antigen is injected. This is an excellent way to activate the immune system and can lead to lifelong immunity. The downside is that people with weak immune systems should avoid this type of vaccine and the vaccines must be stored at very low temperatures to keep the pathogen alive.

Inactivated – A pathogen is killed with chemicals or heat treatments and the dead cells are then injected into the body. Although dead, the immune system will still mount a response. The benefit of this type of vaccine is safety as there is no risk of causing symptoms as the cells are inactivated. It is also easier to store the vaccines as there is no worry about killing the bacteria or virus.

Subunit – Scientists are able to identify a specific protein or carbohydrate from a pathogen and use that to inject into the body without causing any illness.

Toxoid – Some bacteria cause illness by secreting toxins into the body. Scientists can inactivate the specific toxins and inject the dead toxins into the body without causing the disease but training the immune system to mount a response. An example is the vaccine for diphtheria and tetanus.

MRNA/DNA – There is no need for the complete virus or bacteria to produce these vaccines. A specific part of the pathogen’s DNA is all that is required to be injected. The benefit of this type of vaccine is they are cheap to mass produce.

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