A virus that spreads in droplets through the air causes disease among employees at three office sites. A vaccine is available against the virus. Employees work together at the site where they are based.
The table shows the number of employees vaccinated before the start of one year and the number of new cases recorded during that year.
| Site | Total number of employees | Number of employees vaccinated | Number of new cases |
|---|---|---|---|
| A | 1500 | 1050 | 42 |
| B | 2500 | 2375 | 10 |
| C | 1250 | 1125 | 55 |
Before the following year, 300 unvaccinated employees transfer from Site A to Site B. No vaccinated employees transfer, and no other employees transfer.
Calculate the percentage of employees at Site A who were vaccinated.
Predict how the transfer is likely to affect the number of new cases at Site A and at Site B in the following year. Explain your answer using the data.
Use the result for Site C to explain why the managers should investigate other factors before attributing differences in case numbers to vaccination percentage alone.
252 exam-style questions on AQA GCSE Biology 3.1 Communicable diseases, covering 3.1.1 Communicable (infectious) diseases, 3.1.2 Viral diseases, 3.1.3 Bacterial diseases, 3.1.4 Fungal diseases, 3.1.5 Protist diseases, 3.1.6 Human defence systems, 3.1.7 Vaccination, 3.1.8 Antibiotics and painkillers, and 3.1.9 Discovery and development of drugs. Each one has a worked solution and a mark scheme showing where the marks go.