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KS3: Vaccination

In this lesson, students will take part in a simulation to see how vaccines are used to prevent the spread of infections and discover the significance of herd immunity.

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Learning objectives
All students will:
  • Understand that the human body has many natural defences to fight infection, including the 3 main lines of defence
  • Understand that vaccines help prevent a range of bacterial and viral infections
  • Understand that the most common infections such as the common cold or sore throat are not prevented by vaccines
Most students will:


Background Information

Our immune system generally fights any pathogenic microbes that may enter our bodies and helps keep us healthy. It has three major lines of defence:

  • Stopping pathogens from entering our body
  • Non-specific White Blood Cells
  • Specific White Blood Cells

We can help our immune system fight microbes by getting vaccinated. Vaccines are used to prevent, rather than treat infection. A vaccine can be made from weak or inactive versions of the same microbes that make us ill. In some cases, the vaccines are made from cells which are similar to, but not exact copies of, the microbe cells that make us ill. New Messenger RNA (mRNA) vaccines , like some of the COVID-19 vaccines, teach our cells how to make a protein, or piece of protein, to trigger an immune response inside our bodies. Through each of these mechanisms, an immune response is triggered in our bodies and produces antibodies. This is why all vaccines can protect us from getting infected with different diseases. While mRNA vaccines are newly available to the public, researchers have been investigating this for decades. All vaccines, no matter what disease it is for, goes through rigorous processes to ensure that they are safe and effective before being offered to the public.

In this lesson plan, students explore the concept of herd immunity and how vaccinating a large majority of the population can protect everyone. They also learn that different vaccines are required to prevent different infections, and that the types of vaccines needed depend on where we live and travel.

Main activity:
  • Herd Immunity Scenario
Main Activity video
Extension activities:
  • World Map Activity
Curriculum links


  • Working scientifically
  • Cells and organisation
  • Experimental skills and investigations
  • Analysis and evaluation


  • Health and prevention


  • Reading
  • Writing


  • Human and physical geography
  • Geographical skills and fieldwork
Supporting Materials
Teacher sheets
KS3 Vaccinations Teacher Guidance
TS1 Herd Immunity Answers
Student worksheets
SW1 Herd Immunity Scenario
SW2 World Map
Student handouts
SH1-5 Coloured Cards