Table 1 Possible risk factors for invasive meningococcal disease and/or meningococcal pneumonia

• Age (older individuals)

• Smoking

• Close contact with persons with meningococcal infection

• People living in close quarters (e.g. military recruits, university students, Hajj)

• Chronic respiratory conditions (asthma, COPD)

• Coronary artery disease (or CABG)

• Diabetes mellitus

• Cirrhosis

• HIV infection

• Systemic lupus erythematosus

• Sickle cell anaemia (or asplenia)

• Deficiencies in mannose-binding lectin and other genetic abnormalities

• Preceding viral infection (especially influenza)

• Preceding bacterial infection (including S. pneumoniae and H. influenzae)

• Meningococcal serogroups Y, W-135, B

• Immunoglobulin and complement deficiencies

• Haematological malignancies (lymphoma, myeloma)