poxviruses became key players to contain the deadliest virus of its own family: Variola virus
(VARV), the causative agent of smallpox. Cowpox virus (CPXV) and horsepox virus (HSPV)
were extensively used to this end, passaged in cattle and humans until the appearance of
vaccinia virus (VACV), which was used in the final campaigns aimed to eradicate the
disease, an endeavor that was accomplished by the World Health Organization (WHO) in …