World Thrombosis Day

World Thrombosis Day: An Award-Winning, Collaborative Global Movement

Recognized on 13 October, World Thrombosis Day (WTD) focuses attention on the often overlooked and misunderstood condition of thrombosis. With thousands of educational events in countries around the world, WTD and its partners place a global spotlight on thrombosis as an urgent and growing health problem. Open your eyes to thrombosis. Join the WTD campaign today.

The Date

WTD takes place every year on 13 October, the birthday of Rudolf Virchow who was a pioneer in the pathophysiology of thrombosis. A German physician, pathologist, biologist and anthropologist, Virchow developed the concept of "thrombosis" and advanced our understanding of this condition. To learn more, visit the Berlin Museum of Medical History, formerly the Rudolf Virchow's Pathological Museum.


WTD seeks to increase global awareness of thrombosis, including its causes, risk factors, signs/symptoms and evidence-based prevention and treatment. Ultimately, we strive to reduce death and disability caused by the condition.

Our mission supports the World Health Assembly's global target of reducing premature deaths by non-communicable disease by 25 percent by 2025, as well as the World Health Organization’s Thirteenth General Programme of Work 2019–2023, the Montevideo Roadmap 2018-2030 on NCDs and the Political Declaration of UNGA' Third High-level Meeting on NCDs.


  • Highlight the burden of disease (thrombosis in general) and highlight the need for action, specifically underscoring the unrecognized threat and serious consequences (morbidity and mortality) related to venous thromboembolism (VTE) and atrial fibrillation (AFib).

  • Increase public awareness of the significance, risks, signs and symptoms of thrombosis, specifically VTE and AFib as an important cause of thromboembolic stroke.

  • Empower individuals to talk with their healthcare providers about their risk for thrombosis and appropriate prevention. Empower individuals to seek immediate medical attention if they have signs and symptoms.

  • Galvanize organizations in countries across the globe to conduct appropriate and aligned campaigns in their countries and regions.

  • Advocate for "systems of care" to properly prevent, diagnose and treat VTE and AFib.

Previous campaigns

Each year, the WTD campaign is evaluated and its reach and influence are analyzed. Review the campaign's impact via the links below.


WTD was founded in 2014 by the International Society on Thrombosis and Haemostasis (ISTH) in response to members' requests for a focused global awareness day on thrombosis. Led by a global scientific steering committee, more than 175 organizations worldwide participated in the first day, raising much-needed visibility of the condition through special events, educational forums, widespread media coverage and social media. Learn more about the ISTH at

History of the WTD Logo

Did you know that the WTD logo was designed by a patient? When the WTD campaign was founded, Pantep Angchaisuksiri, member of the WTD Steering Committee from Thailand, invited his patient to design a symbol for the WTD campaign. The patient, Ekawat Suwantaroj, created a design that represented both the artery (red color) and the vein (blue color) with a clot (white circle). That design has become the well-known WTD logo that is used today to represent the campaign across the globe.

Ekawat Suwantaroj was diagnosed with severe hemophilia when he was four months old. Partly because of his health condition, drawing and painting became his favorite hobbies. Later, Ekawat received a bachelor's degree in Art and Design in Bangkok. After graduation, he moved to Madison, Wisconsin, where he studied Art and Design for his Master’s degree. He returned to Bangkok and worked as a graphic designer and later as owner of a Bangkok-based graphic design company, iDesign and Creation.

WTD Campaign Team

Louise St. Germain - Director of Marketing, Membership and Public Affairs, ISTH

Samantha (Sam) Nelson - WTD Campaign Manager, ISTH
Sam oversees the WTD campaign, working closely with the global WTD Steering Committee, and ISTH leadership and the Campaign Senior Specialist to manage, strategize and execute the yearly plans for the WTD campaign, including the development and execution of strategic marketing plans, project coordination, management of all aspects of the campaign. Previously, Sam has worked in marketing for large consumer brands. She holds a bachelor’s degree in communications from East Carolina University. 

Barbara Krolak - Senior Campaign Specialist, ISTH
Barbara manages the daily execution of the WTD campaign, including partner communications and collaboration, social media marketing, resource development, and brand strategy. Previously, Barbara has worked in marketing communications at both private and public healthcare-focused organizations. She holds a bachelor’s degree from Appalachian State University.


WTD is an award-winning campaign. It has won the following awards: Association of Association Executives Best Social Media Campaign (2017), A Gold Power of A Award (2016) and Gold Circle Award for Overall Excellence (2015) from the American Society of Association Executives (ASAE) and two prestigous Silver Anvil Awards (2016 & 2015) from the Public Relations Society of America (PRSA). Additional awards include: Gold Circle Merit Award (2016) from the ASAE, Award of Excellence (2015) from the PRSA and the Best in Maryland Awards from the PRSA Maryland Chapter.