Were I to think that a demographic such as young, healthy adults might have "near immunity" to COVID-19, the Japanese that comes to my mind is 不死身.
general context: "Everyone says not to do Y because X might happen. But you want to express a brazen disregard for that advice. You want to express that you could care less if X happens to you and/or, you consider it impossible X could possibly happen to you (for whatever reason)."
Is that correct? What is the correct word that sounds natural in a conversation?