Thanks for your question and concern. It is possible for HSV to get affected in lungs, even though it is not so common. It occurs more in immune-compromised people than that in others. People who have underwent chemotherapy, corticosteroid use etc. fall under the category of immune-compromised people. In such people, immune system cannot fight well against normal infections which can occur naturally. It can go fatal if the infections spread to lungs along with a development of vesicular lesions in trachea. If it involves with pulmonary canal, it can become a life-threatening situation. Hope I have answered your query well. Take care.