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Vaccine academy / Immunisation


What is Immunisation?

Immunisation protects you from harmful diseases before you come into contact with them. It uses your body’s natural defenes to build resistance to specific diseases. If you come into contact with that disease in the future, your immune system remembers it, and responds quickly to prevent the disease from developing. 1

After immunisation, you are far less likely to catch the disease you have been immunised against. If you do catch the disease, your illness will be less severe. Your recovery will be quicker than an unimmunised person’s recovery. 1

Immunization is a global health and development success story, saving millions of lives every year. Vaccines reduce risks of getting a disease by working with your body’s natural defences to build protection. When you get a vaccine, your immune system responds.2

We now have vaccines to prevent more than 20 life-threatening diseases, helping people of all ages live longer, healthier lives. Immunization currently prevents 2-3 million deaths every year from diseases like diphtheria, tetanus, pertussis, influenza and measles.2



What are Vaccines?

Vaccine is a safer substitute for a child’s first exposure to a disease. 3

Vaccines contain the same germs (or parts of germs) that cause infectious diseases. But the germs in vaccines are either killed, or weakened to the point that they don’t cause disease. However, they are strong enough to make the immune system produce antibodies that lead to immunity. In other words, a vaccine is a safer substitute for the first time exposure to a disease. We can get protection without having to get sick. 3



How vaccines work?

The first time when we are infected with a specific germ, the immune system produces antibodies designed to fight it. This takes time . . . usually the immune system can’t work fast enough to prevent the germ from causing disease, so we still get sick. However, the immune system “remembers” that specific germ. If it enters the body again, even after many years, the immune system can produce antibodies fast enough to keep it from causing disease a second time. This protection is called immunity. It would be nice if there were a way to give immunity to a disease without their having to get sick first. 3


Are Vaccines Safe?

Vaccines are safe. Any licensed vaccine is rigorously tested across multiple phases of trials before it is approved for use, and regularly reassessed once it is on the market. Scientists are also constantly monitoring information from several sources for any sign that a vaccine may cause an adverse event. Most vaccine reactions are usually minor and temporary, such as a sore arm or mild fever. In the rare event a serious side effect is reported, it is immediately investigated. 4

In countries where vaccines are manufactured, national or regional regulators oversee a vaccine’s development. This includes approving clinical trials, evaluating their results, and taking decisions on licensing. In deciding, regulators must refer to very strict international standards on acceptable ethical clinical practice. 4





  1. Department of Health Australian Government website. The facts. What is immunisations. Accessed on 18 Feb, 2021.
  2. WHO website. Health Topics. Immunization. Accessed on 18 Feb, 2021.
  3. US CDC website. Vaccines and Immunizations Home. Why Are Childhood Vaccines So Important? Accessed on 18 Feb, 2021.
  4. WHO website. Vaccines and immunization: Vaccine safety. Accessed on 18 Feb, 2021.