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Herd immunity lucky dip

Activity: Participants will act as a virus trying to infect as many ‘people’ as possible in 3 ‘populations’. Infected ‘people’ are red balls, non-infected ‘people’ are yellow balls. Participants will be asked to pull out as many red balls as they can from each tub without being able to see the contents of the tub.

Aim: To highlight how different vaccination rates can affect how many people in the population can be infected by a virus.

How to make:

  • Get three opaque tubs so that you can’t see inside them. Cover the tops of the tubs with a firmly attached, strong bin bag (or similar) with a hole in the top that a hand can fit through.
  • Label the tubs ‘0% vaccinated population’, ‘50% vaccinated population’ and ‘95% vaccinated population’.
  • Fill the 0% vaccinated tub with red fluffy balls (e.g. crafting pompoms). Fill the 50% vaccinated tub with 50% yellow fluffy balls and 50% red fluffy balls. Fill the 95% vaccinated with mainly yellow fluffy balls and a couple of red fluffy balls. You can use different colours if you like but keep to the same format. The yellow balls represent non-infected, healthy people whereas the red balls represent infected people.

What to do: Participants will go into each tub (population) acting as a virus and pull out fluffy balls. All balls should be placed in a clear bowl so that you can estimate the number of different coloured balls. The aim is to see how many ‘people’ you can infect. In the 0% vaccinated population, all balls will be red – therefore infected. In the 50% vaccinated population, the participant will be able to infect around half of the people as they should pull out roughly 50/50 red/yellow balls. In the 95% vaccinated population, they will mostly pull out yellow balls – they will not be able to infect anyone (or hardly anyone). 

For this activity, it is important to have an understanding of herd immunity and also the reasons some people can’t be vaccinated. There has been a steady decline in many routine childhood vaccinations, with many dipping below the recommended 95% coverage. This can lead to outbreaks as shown with the activity and risks lives of those that cannot be vaccinated e.g. young babies, those who are immunosuppressed.