Objectives: To investigate antibody production in asymptomatic and mild COVID-19 patients. Methods: Sera from asymptomatic to severe COVID-19 patients were collected. Microneutralization (MN), fluorescence immunoassay (FIA), and enzyme-linked immunosorbent assay (ELISA) were performed. Results: A total of 70 laboratory-confirmed COVID-19 patients were evaluated, including 15 asymptomatic/anosmia, 49 mild symptomatic, and 6 pneumonia patients. The production of the neutralizing antibody was observed in 100% of pneumonia, 93.9% of mild symptomatic, and 80.0% of asymptomatic/anosmia groups. All the patients in the pneumonia group showed high MN titer (≥1:80), while 36.7% of mild symptomatic and 20.0% of asymptomatic/anosmia groups showed high titer (p < 0.001). Anti-SARS-CoV-2 antibodies could be more sensitively detected by FIA IgG (98.8%) and ELISA (97.6%) in overall. For the FIA IgG test, all patients in the pneumonia group exhibited a high COI value (≥15.0), while 89.8% of mild symptomatic and 73.3% of asymptomatic/anosmia groups showed a high value (p = 0.049). For the ELISA test, all patients in the pneumonia group showed a high optical density (OD) ratio (≥3.0), while 65.3% of mild symptomatic and 53.3% of asymptomatic/anosmia groups showed a high ratio (p = 0.006). Conclusions: Most asymptomatic and mild COVID-19 patients produced the neutralizing antibody, although the titers were lower than pneumonia patients. ELISA and FIA sensitively detected anti-SARS-CoV-2 antibodies.

No abstract

Objective-The current data regarding the association between calcium and phosphorus and cardiovascular disease are lacking. The aim of this study was to explore whether dietary calcium and phosphorus intake and their serum levels are associated with the prevalence of coronary artery calcification (CAC) using cardiac computed tomography in asymptomatic participants without a history of chronic kidney disease or cardiovascular disease. Approach and Results-A cross-sectional study was performed in 23 652 Korean participants (40.8±7.3 years, male 83.5%) without chronic kidney disease (estimated glomerular filtration rate≥60 mL/min per 1.73 m 2 ) or clinically overt cardiovascular disease, who underwent cardiac computed tomographic estimation of CAC scores as part of a general health checkup in addition to completing a self-administered food frequency questionnaire. We assessed the relationship of dietary calcium and phosphorus intake and serum levels with CAC scores using both multivariate-adjusted Tobit models and multinomial logistic regression models. Neither dietary calcium nor phosphorus intake was consistently associated with CAC scores. However, the serum calcium, phosphorus, and calcium-phosphorus product levels were significantly associated with the CAC score ratios. In multivariable-adjusted models, the CAC score ratios (95% confidence intervals) comparing the highest quartiles of serum calcium, phosphorus, and calcium-phosphorus product levels to the lowest quartiles were 1.89 (1.36-2.64), 3.33 (2.55-4.35), and 3.98 (3.00-5.28), respectively (P for trend <0.001). Previous studies suggested that higher serum phosphorus levels (even within normal ranges), but not calcium levels, may be a risk factor for coronary artery disease. Few studies have examined the relationship between dietary intake of calcium and phosphorus and CAC formation. The Framingham cohort study 16 found that total daily calcium intake from the diet and supplements is not associated with increased CAC among 690 women and 588 men over a 4-year follow-up period. Conclusions-ElevatedTo our knowledge, no study has closely analyzed the association between dietary intake of calcium and phosphorus and serum concentrations and the risk of CAC in an Asian population. Assessing the different effects of dietary intake of these minerals and their serum levels on the risk of coronary artery disease may help in identifying factors contributing to the progression of coronary artery atherosclerosis. In this study, we assessed whether dietary calcium and phosphorus intake and their serum levels are associated with CAC using cardiac computed tomography in asymptomatic participants without a history of CKD and CVD. Materials and MethodsMaterials and Methods are available in the online-only Supplement. ResultsThe mean (SD) age and body mass index of the 23 652 participants were 40.8 (7.3) years and 24.3 (3.1) kg/m 2 , respectively. The prevalence of hypertension and diabetes mellitus was 13.8% and 5.3%, respectively. The median (interquartile range) dietary...