The organisations said in a joint statement yesterday that they had been in discussions about merger since October, when a shadow board of trustees was formed.
The statement said the merger would allow them to continue funding their main objectives while building on the education and awareness work of both organisations.
The individual brands will keep their existing names until a new-look charity is launched later in 2013 after a full rebranding and renaming exercise, according to a spokeswoman for the merged organisation.
The chief executive of the Meningitis Trust, Sue Davie, has been appointed chief executive-designate of the merged charity. Alastair Irvine, chair of the Meningitis Trust, has been named chair-designate of the new organisation.
The chief executive of Meningitis UK, Kate Rowland, will be leaving to pursue interests in other cause areas, according to the spokeswoman for the merged organisation. She said there were no planned redundancies and the charities would continue to operate from their existing locations. This is set to be reviewed when the current office leases expire in 2014.
The Meningitis Trust is the larger of the two charities. It had an income of £3.2m in 2012 – an increase of 4.5 per cent compared with 2011 – and has 47 employees. The trust, which is based in Stroud, Gloucestershire, provides support to people affected by meningitis through a helpline and other services such as counselling and creative therapies. It has a remit to raise awareness and fund medical research into the illness.
Meningitis UK concentrates on finding a preventive vaccine against all forms of meningitis and associated diseases. It has 14 employees based at its headquarters in Bristol, and had an income of £1.3m in 2012.
Steve Dayman, the founder of Meningitis UK, said: "By coming together we will have a greater impact in the UK, not only funding pioneering research programmes, but also providing the best education and support services available."