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Measles is a serious disease - AQA - GCSE Biology Combined Science - Question 5 - 2018 - Paper 1
Question 5
Measles is a serious disease. A person can die from measles. Table 3 shows the number of medically confirmed cases of measles in England and Wales between 2012 and ... show full transcript
Worked Solution & Example Answer:Measles is a serious disease - AQA - GCSE Biology Combined Science - Question 5 - 2018 - Paper 1
Step 1
Step 2
Calculate the percentage decrease in the number of medically confirmed cases of measles between 2012 and 2015.
Answer
To calculate the percentage decrease, use the formula:
ext{Percentage decrease} = rac{ ext{old value - new value}}{ ext{old value}} imes 100Substituting the values:
ext{Percentage decrease} = rac{2030 - 91}{2030} imes 100 = rac{1939}{2030} imes 100 \approx 95.5\%Step 3
One reason for the decrease in the number of cases of measles is that more children were vaccinated against the disease. Explain why.
Answer
Vaccinating a large proportion of the population creates herd immunity. When most people are immune, it decreases the likelihood of the virus spreading, as there are fewer individuals for the virus to infect. This reduces the overall number of cases.
Step 4
Explain the differences between antibody production after the vaccine injection and after exposure to the measles virus.
Answer
After the vaccine injection, the body produces a rapid response of antibodies to the harmless antigens in the vaccine. This leads to a quicker and higher peak in antibody concentration, as observed in the graph.
In contrast, following exposure to the actual measles virus, the body may take longer to produce antibodies as it responds to a live virus, typically resulting in a slower initial antibody response with a gradual increase. The antibody concentration is then sustained over a longer period, as immune memory cells are activated to respond to future infections, as reflected in the graph data where the concentration rises more slowly and persists.