The definition of that word has been thoroughly abused. Several pandemics have come and gone. Normally these things are categorized by strain and/or pathology so that people each can be addressed and resolved on its own merits.

Canada's current thinking would have us still referring to first recorded influenza outbreak (1510) as wave 1024 of influenza-1510.

You're right though about natural immunity. The upper respiratory variants will get us there and it'll eventually be one of those things people only worry about in elder care.