The agency was awarded the newly created worldwide brief following a competitive pitch. MS&L will work with The Global Fund on its public, media and political events in 18 countries throughout Asia, Europe, the Middle East, Africa and North America.
'We have been brought on board to support the organisation, and promote its dedication to addressing major health concerns throughout the world in co-ordination with governments, international foundations, and high-profile NGOs,' said MS&L's global healthcare director Monique da Silva.
The MS&L team will work alongside the organisation's in-house comms team.
The Global Fund is a public and private partnership, based in Geneva, dedicated to attracting and distributing additional resources to prevent and treat HIV/Aids, tuberculosis and malaria.
The partnership between governments, civil society, the private sector and affected communities works to supplement existing efforts. To date the fund has committed £7.5bn in 136 countries.
The Global Fund provides a quarter of all international financing for Aids globally, and two-thirds for tuberculosis and malaria.
Programmes supported by the fund are estimated to have prevented more than 2.5 million deaths by providing Aids treatment for 1.75 million people, TB treatment for 3.9 million people and by distributing 59 million insecticide-treated bed nets for the prevention of malaria worldwide.