Since its formation, the medical personnel of the Henry Reeve International Medical Brigade, now composed of about 7,400 voluntary healthcare workers, have been on the front lines providing disaster relief around the world.

Before COVID-19, personnel from the Brigade had treated more than 3.5 million people in 21 countries ravaged by the world's worst natural disasters and epidemics. An estimated 80,000 lives have been saved as a direct result of the Brigade's front-line emergency medical treatments. It was the first team of foreigners to arrive in Pakistan after the 2005 earthquake, and the last to leave six months later. Brigade members worked in Haiti after the disastrous 2010 earthquake and subsequent cholera outbreak.

One of their most heroic acts was in 2014-2015, when the Brigade sent over 400 doctors, nurses and other health workers to West Africa to confront the dangerous Ebola pandemic, working in regions where healthcare facilities and even basic infrastructure such as roads and communications systems were minimal. This team constituted the single largest medical operation on the ground in Sierra Leone, Guinea and Liberia. In recognition of the work of these specialists, the World Health Organization (WHO) awarded them the prestigious Dr. Lee Jong-Wook Memorial Prize for Public Health in 2017.