| |
 | | Over 65s |
 | | People with respiratory disease |
| | | Chronic obstructive pulmonary disease (COPD), bronchitis emphysema, cystic fibrosis, bronchiectasis, and some people with asthma |
 | | People with heart disease |
| | | Angina, heart failure, previous heart attack |
 | | People with kidney disease |
| | | Chronic renal failure, undergoing dialysis, previous kidney transplant |
 | | People with diabetes |
 | | People with a weak immune system |
| | | No spleen or splenic dysfunction, people taking high dose steroids, HIV, cancer, radiotherapy, chemotherapy |
 | | People with a history of: |
| | | Stroke or transient ischaemic attack (TIA), Multiple Sclerosis (MS), some diseases of the central nervous system |