Update 2025-07-01 (PST) (AI summary of creator comment): The creator has clarified the following resolution criteria:
"Natural" extinction of SARS-CoV-2 (without human agency) would resolve the market to YES.
If a successor variant completely displaces the original strain, the market will resolve to NO.
An exception may be made to resolve YES in a scenario where a chimera virus involving SARS-CoV-2 exists, but the original strain is gone.
1,000@JussiVilleHeiskanen I hadn't thought about "natural" extinction when I wrote this question but expect I'd resolve YES in that case.
As for a successor variant completely displacing the original strain: resolves NO. Though maybe I'd resolve YES in extenuating circumstances like "a chimera of SARS-CoV-2 and something else still exists but the original doesn't".