RESUMEN
Inactivated SARS-CoV-2 vaccines have been deployed in a significant portion of the world population, who have widely varied responses to vaccination. Understanding this differential response would help the development of new vaccines for non-responders. Here, we conducted surveillance of anti-Spike receptor-binding domain (RBD) antibody levels in a large cohort of 534 healthy Chinese subjects vaccinated with two doses of inactivated SARS-CoV-2 vaccines. We show that the positive rate of antibodies among vaccinated subjects rapidly wanes as the interval between antibody testing and vaccination increases (14 to 119 days: 81.03%, 363 of 448 subjects; 120 to 149 days: 46.43%, 13 of 28 subjects; more than 150 days: 20%, 1 of 5 subjects). However, the antibodies were maintained at high levels in 16 convalescent COVID-19 patients at more than 150 days after recovery. We also found that increased age and body mass index are associated with decreased antibody levels. Vaccinated subjects who fail to produce antibodies display impaired B-cell activating humoral immunity, which was confirmed in COVID-19 patients without antibodies detected at 4 to 18 days after diagnosis. IMPORTANCE Our study illustrates the immune responses engaged by encountering antigen, highlighting the critical roles of B-cell activating humoral immunity in the body's antibody production.
RESUMEN
BACKGROUND: To investigate the clinical value of multi-index combined detection in the diagnosis of new coronavirus disease 2019 (COVID-19). METHODS: A total of 63 laboratory confirmed patients treated in our hospital were selected as the COVID-19 group, including 28 severe patients and 35 non-severe patients. Another 50 healthy subjects undergoing physical examination simultaneously were selected as the healthy group. Here we performed a study on the laboratory characteristics and explored their efficacy for diagnosis of the disease. RESULTS: Compared with healthy people, the abnormal indicators of patients with COVID-19 are low levels of lymphocytes (LYM), red blood cells (RBC), hemoglobin (HGB), platelets (PLT), total protein (TP), and albumin (ALB), and high levels of monocytes (MON), aspartate aminotransferase (AST), gamma glutamyl transpeptidase (GGT), and C-reactive protein (CRP). The level of MON and CRP in severe patients were significantly increased compared with non-severe pneumonia patients, and indicators such as LYM and ALB were significantly reduced (p < 0.05). The sensitivity and specificity of the combined detection of LYM, MON, RBC, HGB, PLT, TP, ALB, AST, GGT, and CRP was 97.7% and 91.7%, which was higher than the single item (p < 0.05). The sensitivity and specificity of combined detection of LYM, MON, ALB, and CRP to predict the severity of COVID-19 were 96.4% and 73.0%, which were higher than those of separate detections (p < 0.05). CONCLUSIONS: The index of LYM, MON, RBC, HGB, PLT, TP, ALB, AST, GGT, and CRP can be used for the diagnosis of new COVID-19, and the indicators of LYM, MON, ALB, and CRP may be predictors of severe pneumonia. The combined detection of the laboratory indexes can diagnose COVID-19 and predict the severity more effectively and accurately.