YTA. I have a disease similar to Lisa's -- so similar that I think we probably have the exact same condition. (I still have my spleen, but the illness still causes a form of anemia and secondary immunodeficiency.) Lisa is at high risk for serious illness because she does not have a spleen. She's probably on antibiotics to help her immune system, but even so: she is STILL at high risk. She won't die instantly, of course, she probably would not even die at all. But she would get far, far sicker than you would. All of this means that she, like me, is probably pretty worried about coronavirus, and now she also has to worry that her asshole coworkers hate her for expressing her fears in public. A bit of empathy would do you some good.