At any time, around 10% of people carry meningococcal bacteria in the nose and throat, which can cause meningitis, blood poisoning and other serious illnesses. Most people carry these bacteria and never become ill, yet a very small proportion go on to develop these illnesses which can result in life long disabilities or death. The mechanism by which this happens is poorly understood and has been studied in various ways, usually focussing on the bacteria or on the individual, but none has given a definitive answer. This study will be the first of its kind and will assess the interaction between the host and the bacteria at the genetic level, through genetic mapping, helping us to understand what makes some people susceptible to this infection.

At any time, around 10% of people carry meningococcal bacteria in the nose and throat, which can cause meningitis, blood poisoning and other serious illnesses. Most people carry these bacteria and never become ill, yet a very small proportion go on to develop these illnesses which can result in life long disabilities or death. The mechanism by which this happens is poorly understood and has been studied in various ways, usually focussing on the bacteria or on the individual, but none has given a definitive answer. This study will be the first of its kind and will assess the interaction between the host and the bacteria at the genetic level, through genetic mapping, helping us to understand what makes some people susceptible to this infection.

Inclusion Criteria:

• any individual with culture-confirmed IMD in England from 01 September 2015 to 31 August 2019
• written informed consent from the individual, the parent (for children aged <16 years) or next-of-kin (for non-survivors)

Exclusion Criteria:

• any individual who does not fulfil the inclusion criteria

Temporary Exclusion Criteria:

• Critically-ill patients and/or their family member will be only approached when the patient starts recovering from their illness or after they are deceased, on the advice of their clinical team.

any individual with culture-confirmed IMD in England from 01 September 2015 to 31 August 2019 with written informed consent from the individual, the parent (for children aged <16 years) or next-of-kin (for non-survivors)