Mumps and measles, have been almost completely eradicated in the Western Hemisphere before 1990, Singapore

Elaborate and answer following questions

Diseases, like mumps and measles, have been almost completely eradicated in the Western Hemisphere before 1990 because of the introduction of the MMR (measles, mumps and rubella) vaccine. However, during the last years many outbreaks of mumps and measles have been observed in first-world countries such as USA, Canada and UK.

1) Explain what has driven this upsurge?

2) What do we understand under herd immunity? Explain its importance.

3) What do you think should be done when people/parents refuse vaccinations against important pathogens?