Since different infectious diseases have different sources of infection and different antibodies against the virus, patients cured of novel coronavirus pneumonia have antibodies in their bodies to deal with novel coronavirus pneumonia, but they are not immune to all infectious diseases. There are no cases of patients cured of novel coronavirus pneumonia getting sick again, because novel coronavirus is 85% homologous to SARS virus, and antibodies from SARS-era patients can last for 6 months in the body. Based on the results of the study, it is inferred that patients with novel coronavirus pneumonia can maintain antibodies in their bodies for at least 6 months and should not get sick again during this period.