Year 9 Science · Unit 1 · Lesson 9
Challenge Worksheet
Learning Goals
What if…?
Scenario
A major anti-vaccination social media campaign spreads misinformation in Australia, causing MMR (measles-mumps-rubella) vaccination coverage to drop from 95% to 80% nationally over three years. Australia had been declared measles-free since 2014. Scientists know that for measles, one of the most contagious diseases known, vaccination coverage must remain above approximately 93–95% to prevent outbreaks. A traveller arriving in Sydney from an overseas country where measles is still circulating is unknowingly infectious for four days before showing symptoms.
Box 1 Australia maintained measles elimination with vaccination coverage above 95%. If coverage dropped to 80% nationwide, explain what this would mean for Australia's ability to prevent measles outbreaks. In your answer, describe what herd immunity is, why 80% coverage would be insufficient for measles (one of the most contagious diseases known), and what would happen when the infectious traveller arrives.
Box 2 Name and describe three specific groups in the Australian community who cannot receive the MMR vaccine or would be at greatest risk if measles returned. For each group, explain the biological or medical reason they are vulnerable and cannot simply "choose to vaccinate."
Box 3 Australia's No Jab No Pay policy links family payments to vaccination status. Using this scenario as evidence, construct a scientific argument for or against the policy. Your argument must reference the need to maintain high vaccination coverage to protect herd immunity, the rights of vulnerable community members who cannot be vaccinated, and at least one limitation of the policy you choose to defend or oppose.
1. In 2019 in Samoa, measles vaccination coverage dropped to approximately 31% following a tragic vaccine administration error. Measles requires very high vaccination coverage (well above 90%) to prevent spread. Explain why the subsequent measles epidemic spread so explosively in Samoa (5,700 cases in a population of 200,000). In your answer, distinguish between elimination and eradication and explain why vaccination needs to be ongoing rather than a one-off campaign.
2. In 1998, a British doctor named Andrew Wakefield published a fraudulent paper claiming the MMR vaccine caused autism. The paper was retracted in 2010 and Wakefield lost his medical licence, but the damage to public trust in vaccination has persisted for decades. Using your knowledge of how the immune system and vaccines work, explain scientifically why the MMR vaccine cannot cause autism. Then explain why the Wakefield fraud is a particularly serious form of scientific misconduct, beyond simply being wrong.
Wrap Up
In one sentence, what was the main idea of this lesson?