Contamination OCD for a healthcare worker can be very debilitating and can really impact someone's ability to engage in their job. If trauma has fed into their contamination fear it's important that it also gets addressed in treatment. The first step of working on contamination fears are to develop a fear hierarchy with your therapist and be taught response prevention skills; which are basically healthy ways to engage with the ocd thoughts that don't feed the OCD and help you start to get comfortable with uncertainty. Depending on your fear hierarchy we would start at the bottom and find a fear that has a low distress level. For example if the fear is touching surfaces in the hospital and not being able to immediately wash your hands (distress level 3/4), a good exposure would be touching a desk at a nurses station and delay washing your hands for 2-5 mins. It's important they learn skills to not just ruminate or engage in any mental compulsions while doing the exposure. I'd be happy to expand more on this if needed I am an exposure and response prevention certified therapist which is the gold standard treatment for OCD.