Will resolve based off https://www.cdc.gov/poxvirus/mpox/response/2022/index.html (or an equivalent page if the CDC's dashboard for monkeypox moves to another URL).

Currently it shows 32,063 cases and 58 deaths in the US since the start of the outbreak. If on December 31st the dashboard reports at least 100 deaths (equivalent to 42 additional deaths happening between now and the end of the year), this will resolve to Yes. Otherwise will resolve to No.

Note that the dashboard shows the cumulative deaths count since the start of the monkeypox outbreak and this is what the market will resolve on.