Characteristics of virus and antibody response in an immunocompromised patient with persistent SARS-CoV-2 infection.

We have previously reported a clinical case in which a hospitalized patient with a history of hematopoietic stem cell transplantation for acute myeloid leukemia was persistently infected with SARS-CoV-2. This study investigated the neutralizing activity of patient sera against cultured viruses isolated at each time point. We also continued to decipher and analyze the whole-genome sequence of the virus. The results showed that the neutralizing activity against the cultured virus at each time point was higher in the sera collected in the late stage of infection. However, the cultured virus collected in the late stage of infection was less likely to be neutralized not only by the sera collected in the early stage of infection but also by the sera collected in the late stage. Moreover, the virus mutated in a manner that allowed it to escape neutralizing antibodies in a host vulnerable to prolonged infection, such as immunocompromised patients.