medical thriller film depicting the rapid spread of a virus, inspired by pandemics such as the 2002–2004 SARS outbreak and the 2009 flu pandemic. https://en.wikipedia.org/wiki/Contagion_(2011_film)
For a slightly different, less realistic, sci-fi bio-thriller, Michael Crichton's "Andromeda Strain." https://en.wikipedia.org/wiki/The_Andromeda_Strain
For a medical thriller film depicting the rapid spread of a virus...see any zombie movie that has ever been made.
A couple of good, 'based on a true story' options are below. '93 Days' on Netflix - Ebola outbreak in Lagos, Nigeria. Pretty good. 'The Hot Zone' - Mini-series based on the book of the same name. Decent, but as usual, the book was better. 'Pandemic' - also on Netflix, but this is a docu-series on the current efforts to battle the flu. Haven't watched it yet, but it's in the queue.