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Background The clinical course of COVID-19 may vary significantly. The presence of comorbidities prolongs the recovery time. The recovery in patients with mild-to-moderate symptoms might take 10 days, while in those with a critical illness or immunocompromised status could take 15 days. Considering the lack of data about predictors that could affect the recovery time, we conducted this study to identify them. Methods This cross-sectional study was implemented in the COVID-19 clinic of a teaching and referral university hospital in Tehran. Patients with the highly suggestive symptoms who had computed tomography (CT) imaging results with typical findings of COVID-19 or positive results of reverse transcriptase-polymerase chain reaction (RT-PCR) were enrolled in the study. Inpatient and outpatient COVID-19 participants were followed up by regular visits or phone calls, and the recovery period was recorded. Results A total of 478 patients were enrolled. The mean age of patients was 54.11 ± 5.65 years, and 44.2% were female. The median time to recovery was 13.5 days (IQR: 9). Although in the bivariate analysis, multiple factors, including hypertension, fever, diabetes mellitus, gender, and admission location, significantly contributed to prolonging the recovery period, in multivariate analysis, only dyspnea had a significant association with this variable (p = 0.02, the adjusted OR of 2.05; 95% CI 1.12–3.75). Conclusion This study supports that dyspnea is a predictor of recovery time. It seems like optimal management of the comorbidities plays the most crucial role in recovery from COVID-19.

Lactic acid bacteria (LAB) play an important role in the food industry as starter cultures to manufacture fermented food, and as probiotics. In recent years, there has been an increasing interest in using LAB cultures for biopreservation of food products. It is therefore of great interest to study the detailed metabolism of these bacteria. This study aimed at developing an efficient analytical protocol for real-time in vitro NMR measurements of LAB fermentations, from sample preparation, over data acquisition and preprocessing, to the extraction of the kinetic metabolic profiles. The developed analytical protocol is applied to an experimental design with two LAB strains (Lactobacillus rhamnosus DSM 20021 and Lactobacillus plantarum subsp. plantarum DSM 20174), two initial pH levels (pHi 6.5 and 5.5), two levels of glucose concentration (2.5 and 0.25 g/l), and two batch fermentation replicates. The design factors proved to be strongly significant and led to interesting biological information. The protocol allowed for detailed real-time kinetic analysis of 11 major metabolites involved in the glycolysis, pyruvate catabolism, amino acid catabolism and cell energy metabolism. New biological knowledge was obtained about the different patterns of glutamine and aspartic acid consumption by the two strains. It was observed that L. plantarum consumes more glutamine at low pH (pH 5.5) whereas the opposite applies to L. rhamnosus. Regarding aspartic acid, both of the strains consume it higher at low pH, and overall L. plantarum consumes it more. L. rhamnosus did not consume aspartic acid at pH 6.5. The developed analytical protocol for real-time in vitro NMR measurements of bacterial metabolism allows a relatively easy investigation of different fermentation factors such as new strains, new substrates, cohabitations, temperature, and pH and has a great potential in biopreservation studies to discover new efficient bioprotective cultures.