Antibodies to the receptor-binding domain of the SARS-Cov-2 spike protein: association with age, pneumonia, duration of the period after COVID-19.

Despite the rapid accumulation of facts about the humoral immune response in COVID-19, there are still no evidence-based answers to questions about the factors influencing the level and duration of the detection period of antibodies to SARS-CoV-2 in the blood. Objective(s): To assess the prevalence, clinical and demographic associations of IgG antibodies to RBD of the SARSCoV-2 spike protein at different times after COVID-19. Materials and methods. Residents of the Altai region of Russia, Caucasians aged 20-93 years, who had COVID-19 from May 2020 to February 2021 (n = 314), took part in a onetime observational study. The level of antibodies in the blood was measured by enzyme-linked immunosorbent assay 1-14 months after the onset of the clinical manifestation of CO-VID-19. Results. Anti-RBD IgG antibodies of the SARS-CoV-2 spike protein were detected in 86.9% of the study participants. The dependence of the antibody titer on the duration of the period after COVID-19 was not revealed. The antibody titer was positively correlated with the complication of CO-VID-19 pneumonia and the volume of lung tissue lesions. The presence of pneumonia COVID-19 and the volume of lung tissue lesions are positively associated with age. Age positively correlated with antibody titer regardless of the pneumonia COVID-19 in the anamnesis. Conclusion. IgG antibodies to RBD of the SARS-CoV-2 spike protein are present in most of the COVID-19 patients. The titer of these antibodies in adults depends on age, complications of pneumonia COVID-19, and probably persists up to 14 months after the first symptoms of infection appear.Copyright © 2022 Interregional public organization Association of infectious disease specialists of Saint-Petersburg and Leningrad region (IPO AIDSSPbR). All rights reserved.

The burden of a new coronavirus infection in a Children's multidisciplinary hospital in St. Petersburg 2020-2021.

Objective: To describe the burden of COVID-19 in a children's multidisciplinary hospital for two years of the pandemic, taking into account of age, severity of the disease, the spectrum of underlying conditions and the intensive care need. Method(s): An assessment of 6048 cases of COVID-19 in patients under 18 years of age hospitalized from March 26, 2020 to December 31, 2021 was carried out. The diagnosis was confirmed by PCR on an outpatient basis or after hospitalization with the help of diagnostic kits registered in the Russian Federation. The features of the work of a children's multidisciplinary hospital in new conditions, the dynamics of hospitalization, age characteristics and new coronavirus (CV) infection severity in the pandemic development process are presented. The analysis of the underlying condition's structure depending on the severity of the disease, as well as the need and volume of therapy in the intensive care unit. The frequency and main characteristics of children's multisystem inflammatory syndrome (MIS-C) in hospital conditions, long-term PCR positivity and its effect on the duration of inpatient treatment of children have been established. Result(s): The spread of SARS-COV-2 in St. Petersburg required a radical change in the work of the children's multidisciplinary hospital. During the two years of the pandemic, four waves of hospitalization of children with new CV were revealed, differing in duration, intensity, and frequency of lung damage, but having no significant differences in the proportion of severe forms of the disease (1.7-2.8% of cases). Intensive therapy was required in 3.6% of cases, of which only 1/3 was due to the severe course of COVID-19 with a lung lesion volume of up to 100%. In 1/3 of cases, patients had risks of developing severe forms and in 1/3 - other pathology. Severe course of new CV was significantly more often accompanied by the need for respiratory support, anticoagulants and anti-inflammatory therapy. Contributing factors of severe forms and unfavorable outcomes were: pathology of the central nervous system, genetic diseases and malformations, obesity, as well as chronic bronchopulmonary pathology. Mortality in the hospital was recorded only among children with severe underlying conditions (0.1% of cases). D-MVS was registered significantly more often in boys (7 out of every 10 patients), accounting for 1.2% of cases of hospitalization of children with new CV over the entire period. Convalescent PCR-positivity in the outcome of COVID-19 was detected in 1/3 of children, significantly more often during the autumn-winter waves of the pandemic and among patients of high school age. Conclusion(s): New CV is gradually strengthening its position in the structure of acute respiratory pathology in children. Some of SARS-COV-2 infection cases is accompanied by extensive lung damage, as well as severe systemic inflammation independently or in the other infectious diseases structure, induction of the debut of various somatic pathology is not excluded. The presented data confirm the need for increased attention at high risk of adverse respiratory diseases outcomes children. All severe cases of COVID-19 in children require a personalized approach, taking into account the existing background diseases and possible options for the progression of the process. MIS-C should be considered as a systemic inflammatory response syndrome within the framework of an infectious disease of various etiologies, differentiated with Kawasaki disease and the debut of systemic diseases. The long-term PCR-positivity in the outcome of COVID-19 requires further study to address the need and nature of therapy in order to prevent further spread of infection in the population.Copyright © 2022 Interregional public organization Association of infectious disease specialists of Saint-Petersburg and Leningrad region (IPO AIDSSPbR). All rights reserved.

Fine-Grained Assessment of COVID-19 Severity Based on Clinico-Radiological Data Using Machine Learning.

BACKGROUND: The severe and critical cases of COVID-19 had high mortality rates. Clinical features, laboratory data, and radiological features provided important references for the assessment of COVID-19 severity. The machine learning analysis of clinico-radiological features, especially the quantitative computed tomography (CT) image analysis results, may achieve early, accurate, and fine-grained assessment of COVID-19 severity, which is an urgent clinical need. OBJECTIVE: To evaluate if machine learning algorithms using CT-based clinico-radiological features could achieve the accurate fine-grained assessment of COVID-19 severity. METHODS: The clinico-radiological features were collected from 78 COVID-19 patients with different severities. A neural network was developed to automatically measure the lesion volume from CT images. The severity was clinically diagnosed using two-type (severe and non-severe) and fine-grained four-type (mild, regular, severe, critical) classifications, respectively. To investigate the key features of COVID-19 severity, statistical analyses were performed between patients' clinico-radiological features and severity. Four machine learning algorithms (decision tree, random forest, SVM, and XGBoost) were trained and applied in the assessment of COVID-19 severity using clinico-radiological features. RESULTS: The CT imaging features (CTscore and lesion volume) were significantly related with COVID-19 severity (p < 0.05 in statistical analysis for both in two-type and fine-grained four-type classifications). The CT imaging features significantly improved the accuracy of machine learning algorithms in assessing COVID-19 severity in the fine-grained four-type classification. With CT analysis results added, the four-type classification achieved comparable performance to the two-type one. CONCLUSIONS: CT-based clinico-radiological features can provide an important reference for the accurate fine-grained assessment of illness severity using machine learning to achieve the early triage of COVID-19 patients.

Response of local disease at magnetic resonance after salvage radiotherapy for prostate cancer

Purpose or Objective To assess the pattern of response on dynamic contrast enhancement magnetic resonance imaging (DCE-MRI) of presumed local lesions in the setting of salvage radiotherapy (sRT) after radical prostatectomy (RP). Materials and Methods The present prospective study (NCT04703543) was conducted at a single Institution between August 2017 and June 2020. Eligibility criteria were: undetectable prostate specific antigen (PSA) after RP;biochemical recurrence (2 consecutive PSA rises to 0.2 ng/ml or greater);a presumed local failure at DCE-MRI (early/fast enhancing discrete lesion on DCE sequences);no distant metastases at choline-PET/CT;no previous history of androgen deprivation therapy and/or RT. Accrued patients underwent sRT as it follows: 66-69 Gy/30 fractions to the prostatic bed, 73.5 Gy/30 fractions to the local failure at DCE-MRI, 54 Gy/30 fractions to the pelvic nodes (when treated). All patients were offered DCE-MRI 3 months after sRT, and repeated at 3-month intervals until complete disappearance or a maximum of 4 scans. The endpoint of the study, complete response (CR), was defined as the complete disappearance of the target lesion at DCE-MRI. In case of misses before CR, the observation was considered as a persisting partial response (PR). Results 62 patients with 72 nodules at DCE-MRI were accrued. All patients underwent the 1st DCE-MRI at a median of 3.3 months (IQR: 3.1-4.1) after sRT, 33 patients (53.2%) presented a CR, 27 (43,5%) a PR, 2 (3.2%) no response. One patient, implanted with a cardiac device, did not undergo further MRI. Three more patients declined further testing after the 1st (N=2) or the 2nd (N=1) re-evaluation due to the COVID-19 pandemic. Twenty-eight patients underwent a 2nd DCE-MRI after a median of 6.8 months (IQR: 6.5-7.6) from sRT, 20 had a CR, 8 had a PR. After a median time of 10.7 months (IQR: 10.6-12.6), 6 patients were scanned for a 3nd DCE-MRI: 4 CR, 2 PR. The last patient reported a CR after 16.7 months. The majority (94.3%, 95%CI: 88.0-100.0%) of lesions had completely disappeared by the 3rd re-evaluation or a median time of 10.7 months from the end of sRT (Figure).(Figure Presented) Independent predictors of CR at 1st re-evaluation on multivariable analysis were: the volume of the lesion at pre-sRT DCEMRI (OR 0.076, 95%CI 0.009-0.667;p=0.02), the time of re-evaluation from treatment (OR 3.39, 95%CI 1.156-9.993;p=0.026) and the PSA percent decrease at the 5th week of sRT (OR 1.02, 95%CI 0.999-1.050;p= 0.058) (Table). (Table Presented) Receiver-operating characteristic curve (ROC) analysis identified the best cut-off on CR for baseline volume at 0.545 cc, AUC 0.683 (95%CI: 0.548-0.818, p=0.014). The probability of a CR for lesions larger than the cut-off identified at ROC analysis was only around 75% at 10.7 months. Conclusion The vast majority of local lesions disappears at DCE-MRI after sRT, though larger lesions may require more than 10 months from treatment end.