Immunization of mice with vaccinia virus Tiantan strain yields antibodies cross-reactive with protective antigens of monkeypox virus

Dear Editor,Since the global eradication of smallpox in the 1980s,monkeypox has become the most severe infectious disease caused by pathogenic orthopoxvirus(OPXV)infection.Monkeypox virus(MPXV)is the causative pathogen of monkeypox and was classified as a category of human infectious pathogen by theMinistry of Health of the People's Republic ofChina in 2006.Monkeypox has traditionally been endemic in West and Central Africa since it was discovered nearly 70 years ago(Breman et al.,1980).However,beginning in early May 2022,a sudden outbreak of monkeypox has taken place and remains ongoing in more than 100 nonendemic countries and territories located at Europe,Americas,and Asia(https://worldhealthorg.shinyapps.io/mpx_global/).