The SIOP Secretariat supports the Board and the SIOP members in pursuing the Society’s mission.

Mrs Susanne Wollaert
Chief Executive Officer
Susanne manages the day-to-day business and supports the board and members on successfully advancing our objectives through the ever-changing and expanding health care environment.
She comes with +10 years of experience in the management of physician healthcare associations and has developed expertise in all the main aspects of running a professional society, including strategy and operations, congresses and meetings, budget responsibility, program development, and communications and publishing activities. She holds a BSc in Int. Hospitality Management (Major in Marketing) from the École hôtelière de Lausanne. She is based in Meierskappel, Switzerland.
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Mrs Anelia Atanasova
Administrative Coordinator
Anelia supports the Secretariat, the Board of Directors and the leaders of the Society’s Networks, Committees, Working Groups and Task Forces with the day-to-day business of the Society, its various activities, and operations.
She is a lawyer by profession and used to practice in the legal field for 6 years, graduated from the Bulgarian University of Veliko Tarnovo in 2010. She has more than 5 years experience with a non-profit organisations, which developed crucial skills like attention to culture, community and mission which are a continuous focus in her work. She was involved in different international projects regarding disadvantaged groups, building communications with different parties and coordination of project activities where in the role of Project coordinator worked for Open Society Institute, Sofia, Trust for Social Achievement and others. She took part in different activities for implementation of the project "T.E.A.M.2 - Together wE Achieve More" implemented by the Secretariat of the NCCEII through the administration of the Council of Ministers, funded by the European Union’s Rights, Equality and Citizenship Programme (2014-2020). She has leading role to motivate project teams and monitor project activities, coordinate work with consultants and volunteers in different projects. She is based in Montana, Bulgaria.
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Mrs Tessie Laub
Executive Director for Programmes and Strategy
Tessie leads on implementation of our Strategy 2021-2025 in collaboration with the Board of Directors and manages the programme work of the Society.
She is a seasoned programmes specialist who has worked on health, education, and child protection in both development and humanitarian contexts. Prior to SIOP, Tessie worked for the Int’l Rescue Committee in Ethiopia, Bulgaria and the USA, responding to refugee crises and supporting humanitarian response to situations of internal displacement globally. Previously, she worked as a Sr. Coordinator at the Inter - Agency Network for Education in Emergencies and as a Program Specialist at the Watchlist of Children and Armed Conflict, both in New York City. She holds a BA degree in International Relations from Mount Holyoke College and a MA in Politics from Brandeis University. In her spare time, she likes traveling, hiking, and folk-dancing. She is based in Sofia, Bulgaria.
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Olga Kozhaeva
Director, Policy Affairs
Olga leads our advocacy campaigns, supports our relationship with WHO, and manages the Advocacy Committee.
Nancy Anderson
Marketing and Communications Manager
Nancy manages our Marketing and Communications strategy, channels and content.
She has 7 years’ experience in charity communications. Before SIOP, she led the communications activity for a global non-profit organisation that represents the voice of people with intellectual disabilities and their families and as a result of this work, values accessible, dynamic and concise messaging. She enjoys driving engagement through campaigns, publications, platforms and events and connecting members to opportunities to create real social change and measurable impacts. She is based in Newcastle-upon-Tyne, UK. She is based in Newcastle-upon-tyne.
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Grigor Nalbantov
Legal professional with extensive experience, focusing on Law at New Bulgarian University, Sofia, Bulgaria
Served as a Junior Lawyer at the law firm "Kolcheva, Smilenov, Koev & Partners," Sofia, Bulgaria. Proficient in negotiating, mediating, and drafting various contracts, powers of attorney, and special operational procedures for the company. Transitioned to the role of Expert at Elana Holding, Sofia, Bulgaria. Involved in a wide range of tasks, including creating presentations and monthly reports for investors, presenting details on deals, clients, and legal proceedings. Responsibilities included maintaining, coordinating, and updating client databases, archives, and contacts.Experienced in team leadership, planning, delegating tasks, and document verification. Assisted with administrative tasks for Regional Representatives and clients. Participated in the preparation of transaction documents and organized meetings with clients and investors. Currently serving as a Membership Coordinator at Kenes International Bulgaria EOOD since December 2022. Experienced in team leadership, planning, delegating tasks, and document verification.
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SIOP staff are available to answer any questions and to give more information on the various activities of the Society including SIOP membership. The SIOP Secretariat does not respond to any questions regarding treatment and is not in the position to assist patients medically and/or financially. For such questions, we recommend that you consult our partnering family and patient organisations’ country offices and contact them directly.

SIOP Office, Stöcklen 16, 6344 Meierskappel, Switzerland
Tel: +41 78 687 9163