Chickenpox is not smallpox; they are completely different diseases. Smallpox is a virulent infectious disease caused by the smallpox virus. Smallpox virus is categorized as a genus of poxviruses in the family Poxviridae, and is one of the four genera of poxviruses that cause disease in humans. Smallpox virus infection often leads to death due to secondary bacterial infections and systemic organ damage. Chickenpox is a self-limiting disease caused by varicella-zoster virus, which belongs to the herpesvirus family. People infected with chickenpox will present with blisters, macules, papules and other skin lesions, and the prognosis is generally good. A small number of severe cases or complications of encephalitis and pneumonia have a poorer prognosis and a risk of causing death, but they are far less lethal than smallpox. Although chickenpox and smallpox are two completely different diseases, they both pose a certain threat to human health. Since smallpox has been completely eliminated, there is no need to worry too much about the possibility of future infections, but the prevention of chickenpox should not be taken lightly.