An estimated 14 million people in England are living with two or more chronic conditions, referred to Multiple Long-Term Conditions (MLTC). We know that people living with MLTC have a higher risk of being admitted to hospital and of dying during the winter season. However, it is not known which combinations of MLTC are associated with the highest risk of these poor health outcomes, and if vaccinations (against COVID-19 or seasonal flu) can lower this risk.

This study will use an anonymised electronic database of patient records to carry out statistical tests with traditional mathematical methods and automated computer (machine learning) approaches to tell us which combinations of disease are most likely to have a high risk of these outcomes, and if this risk can be reduced by vaccination.

By being able to more accurately identify people with specific combinations of MLTC who are most at risk of hospitalisation and death, public health interventions such as education and vaccinations can be tailored to improve care. Doctors will also have the necessary information to better support them in treating this group of people.