The study models one-time mass mpox (MPXV Clade I) vaccination strategies in 47 sub-Saharan countries from 2025 to 2050 to prevent outbreaks. The model is based on data on Clade Ia and Ib epidemics in the Democratic Republic of the Congo, demographic data, contact patterns, and historical smallpox vaccination coverage. It is estimated that at least 20 countries will need vaccination in 2025 and 36 in 2050 to protect against national outbreaks. In the 11 Clade I affected countries, the minimum required vaccine coverage in 2025 is from 0%–4.8% to 14.5%–19.5% according to increasing sexual transmission, in 2050 from 0%–10.8% to 22.6%–26.0%. The priority age group shifts from 0–4 years to 20–29 years with higher sexual transmission. The projections are based on evidence of Clade I transmission in the DRC as of December 2024. The findings highlight the need for targeted vaccination of high-risk groups according to each country's epidemiological situation.