It has been less than a week since Sierra Leone, Guinea and Liberia, the three countries most affected by the worst known Ebola outbreak in history, were declared free of transmission of the virus. But there has already been a setback, with the death of a woman in Sierra Leone from the disease.

       Dr. Lee Norman, chief medical officer at The University of Kansas Hospital, says in the video that it’s important not to let our guard down, and that hospitals should continue to screen patients, especially those who have traveled to those areas, for the disease. He also explains what it means to be declared “Ebola free” and whether the disease is really gone, how it’s devastated the countries it’s hit, how the development of a vaccine is progressing and why it’s best for hospitals to have permanent, not just temporary, isolation units.