SZU-MIN HSIEHSUNG-CHING PANSHEY-YING CHENHuang P.-F.SHAN-CHWEN CHANG2020-03-242020-03-2420041058-4838https://scholars.lib.ntu.edu.tw/handle/123456789/478760The potential for bioterrorism involving smallpox has led to a debate about the durability of protective immunity against smallpox from vaccination. By assessing the T cell reactivity to vaccinia virus in a healthy population, we show that subjects who were vaccinated within the past 3 decades and who have a visible vaccination scar had remarkable T cell reactivity. However, person who were vaccinated within the past 3 decades but who do not have a scar and those who were vaccinated >4 decades ago had responses as low as those in unvaccinated subjects. Thus, we estimate that the significant T cell memory response to vaccinia virus from successful vaccination may persist for only 20-30 years. Furthermore, we found the vaccinia-specific cellular immunity could be easily assessed by determination of the frequencies of vaccinia-specific CD69 expression on T cell subsets. These data may help in the development of public health strategies to counter bioterrorism threats associated with smallpox.[SDGs]SDG3vaccinia vaccine; adult; age distribution; aged; article; controlled study; health status; human; immunoreactivity; nonhuman; normal human; population research; priority journal; scar; T lymphocyte; time; vaccination; vaccinia; Vaccinia virus; Adolescent; Adult; Age Distribution; Aged; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; Bioterrorism; Child; Child, Preschool; Humans; Immunity, Cellular; Immunologic Memory; Lymphocyte Activation; Middle Aged; Population; Smallpox Vaccine; T-Lymphocyte Subsets; T-Lymphocytes; Vaccinia virusjournal article10.1086/380460146794522-s2.0-0347859218