Effective strategy to mitigate the ongoing pandemic of 2019 novel coronavirus (COVID-19) require a comprehensive understanding of humoral responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the emerging virus causing
COVID-19. The dynamic profile of viral replication and shedding along with
viral antigen specific antibody responses among
COVID-19 patients started to be reported but there is no consensus on their patterns. Here, we conducted a serial investigation on 21 individuals infected with SARS-CoV-2 in two medical centres from Jiangsu Province, including 11 non-severe
COVID-19 patients, and 5 severe
COVID-19 patients and 5 asymptomatic carriers based on
nucleic acid test and clinical symptoms. The longitudinal swab samples and sera were collected from these people for
viral RNA testing and antibody responses, respectively. Our data revealed different pattern of seroconversion among these groups. All 11 non-severe
COVID-19 patients and 5 severe
COVID-19 patients were seroconverted during hospitalization or follow-up period, suggesting that serological testing is a complementary assay to
nucleic acid test for those symptomatic
COVID-19 patients. Of note, immediate antibody responses were identified among severe cases, compared to non-severe cases. On the other hand, only one were seroconverted for asymptomatic carriers. The SARS-CoV-2 specific antibody responses were well-maintained during the observation period. Such information is of immediate relevance and would assist
COVID-19 clinical diagnosis, prognosis and
vaccine design.