Abstract
To investigate the clinical characteristic of domestic coronavirus disease 2019 (COVID-19) patients after vaccination campaign conducted in China. According to vaccination status and months from first vaccine dose to infection detection, patients were divided into unvaccinated, <3 months, 3-6 months, and >6 months groups. The information of demographic and clinical characteristics, laboratory and thoracic computed tomography (CT) findings, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid and IgM, IgG antibodies was retrospectively collected. Therapeutic approaches, temperature-normalizing and viral shedding times, outcomes were also summarized. SARS-CoV-2 antibody levels were further analyzed based on the other following variables: time from second vaccine dose to infection, vaccine dose, the interval from the first to the second dose, and vaccine brand. Among 208 COVID-19 patients, 13 (6.28%) were unvaccinated. No significant differences in demographic and clinical characteristics, laboratory and CT findings, and SARS-CoV-2 nucleic acid loads were detected between groups (all p > 0.05). In comparison with the unvaccinated group, the median SARS-CoV-2 IgG levels were noticeably increased in those vaccinated groups (0.603 in unvaccinated, 15.925 in <3 months, 14.04 in 3-6 months, and 4.94 in >6 months, respectively, p < 0.05). However, SARS-CoV-2 IgG levels were not altered between groups divided based on the other variables. Vaccination does not affect the clinical characteristics in COVID-19 patients. COVID-19 patients with vaccination have high SARS-CoV-2 IgG levels. Underscore the necessity of rapid implementation of vaccination campaigns can be speculated.