Following a vaccination, a person can become immune to the specific disease. This immunity gives protection against illness in an individual. The majority of the population must be vaccinated against serious diseases, which can reduce the chance of people coming into contact with specific pathogens, leading to herd immunity.
Explain what happens to the number of measles cases after 1968.
The measles vaccine was introduced in 1968 which caused a sharp decline in the number of measles cases. This happened because more people were immune to the disease so it did not spread.
Describe how the introduction of the new MMR vaccine affected the cases of measles recorded.
A new MMR vaccine was introduced in 1988, which caused a further sharp decline in recorded cases falling to almost zero cases in 2004.