On Oct. 16, 2024, a National Institutes of Health (NIH)-funded clinical trial of an mpox vaccine in adolescents found it was safe and generated an antibody response equivalent to that seen in adults, according to a planned interim analysis of study data. Adolescents are among the population groups affected by mpox in the current Clade I mpox outbreak.

The first human case of mpox was recorded in 1970 in the Democratic Republic of the Congo (DRC). Two types of the virus that causes mpox have been identified. Clade I is endemic in Central Africa and can cause severe illness. Clade II, endemic in West Africa, caused the global mpox outbreak that began in 2022 and tends to result in milder illness.