(a)[1]
Name the pathogen responsible for measles.
(b)[3]
Use the data in Fig. 6.1 to describe the pattern shown in the number of cases of measles reported to the World Health Organization (WHO) between January 2008 and December 2012.
(c)[4]
The WHO is coordinating a vaccination campaign to reduce the number of measles cases. About seven to ten days after receiving the measles vaccination, the concentration of antibodies in the blood begins to rise. Describe what happens in the blood after the injection of a measles vaccine until the concentration of antibodies in the blood begins to increase.
(d)[2]
Explain why countries with established vaccination programmes still have cases of measles.