Among persons born in China before 1980 and tested for vaccinia virus Tiantan strain (VVT), 28.7% (137/478) had neutralizing antibodies, 71.4% (25/35) had memory B-cell responses, and 65.7% (23/35) had memory T-cell responses to VVT. Because of cross-immunity between the viruses, these findings can help guide mpox vaccination strategies in China.
Keywords: China; memory B cell; memory T cell; monkeypox; mpox; neutralizing antibodies; smallpox; vaccine-preventable diseases; vaccinia virus; viruses.