Boris Johnson is visiting the Royal Cornwall Hospital in Treliske to announce plans to improve immunisation.
It's his first visit to the region since becoming Prime Minister - and he's taking the opportunity to promise change for the region, admitting that the South West's unique needs have not been properly met by previous governments “for many years".
Mr Johnson plans to lay out a number of ways the Government wants to improve vaccination rates, including for measles, mumps and rubella (MMR).
He will also outline plans to boost the number of children and young people receiving vaccinations.
The trip to the South West is part of a series of visits to hospitals across the country.
He will meet local doctors and nurses serving on the front line and speak to them about what support they think the NHS needs.
The UK lost its 'Measles-free' status three years after the virus was eliminated.
The number of children who receive the top-up MMR jab is 87%, which the Government says, is likely to have impacted the spread of the virus.