A nurse checks that a child has received all scheduled vaccinations before a family visit to an island where measles outbreaks sometimes occur. Fig. 1 shows...
Question 1 Report
A nurse checks that a child has received all scheduled vaccinations before a family visit to an island where measles outbreaks sometimes occur. Fig. 1 shows a simplified drawing of a vaccine being injected into muscle. The vaccine contains harmless forms of antigens from a pathogen, rather than active disease-causing cells. Several weeks later, the child is exposed to the real measles virus while travelling. The child does not develop symptoms, although other unvaccinated visitors become ill.
(a) Identify what the vaccine contains that causes an immune response. [1]
(b) Explain why the child is unlikely to develop measles after later exposure to the virus. [2]
(c) Give one way widespread vaccination can protect people who cannot receive a vaccine. [1]
Answer Details
(a) Antigens [1] (b) Memory cells remain in the body [1]; they produce antibodies rapidly / in a larger amount when the virus enters [1]. [2] (c) Fewer people can pass the pathogen on / transmission is reduced, so vulnerable people are less likely to meet the pathogen. [1]
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