- Cardiac disease, including cyanotic congenital heart disease, coronary artery disease and congestive heart failure.
- Chronic respiratory conditions, including suppurative lung disease, chronic obstructive pulmonary disease and severe asthma.
- Other chronic illnesses requiring regular medical follow up or hospitalisation in the previous year, including diabetes mellitus, chronic metabolic diseases, chronic renal failure, and haemoglobinopathies.
- Chronic neurological conditions that impact on respiratory function, including multiple sclerosis, spinal cord injuries, and seizure disorders.
- Impaired immunity, including HIV, malignancy and chronic steroid use.
