A Study Evaluating the Safety and Immunogenicity of MVA Strain Monkeypox Attenuated Live Vaccine

Inclusion Criteria: * On the day of enrollment, individuals aged 18 years or older with a history of smallpox vaccination must have been born before 1980; * Can provide legal proof of identity; * Be able to understand the experimental procedure and sign a written informed consent form, expressing agreement to participate in the experiment; * Be able to participate in all planned follow-up visits and comply with all trial procedures (such as completing diary/contact cards and being able to return for visits); * On the day of enrollment, the body temperature was less than 37.3 ℃ (axillary temperature); * Men and women of childbearing age who have no plans to have children within 6 months and agree to take effective contraceptive measures within 6 months after receiving the experimental vaccine. Exclusion Criteria: * Individuals with a history of smallpox, monkeypox, or close contact with monkeypox in the past; * Individuals who are allergic to any ingredients of eggs, vaccines, or substances used in production processes, or have a history of other severe allergies; * Use immunoglobulin and/or any blood products within 3 months prior to administering the trial vaccine, or plan to use them during the trial period; * Currently using salicylate drugs or planning long-term use during the trial period; * Have used any experimental or unregistered products within one month prior to administering the trial vaccine, or plan to use them during the trial period; * Administer inactivate…