Convalescent COVID-19 Research Articles

Alterations in T cell immunity over 6–12 months post-COVID-19 infection in convalescent individuals: a screening study

Acute COVID-19 is a viral infection caused by a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that results in dramatically decreased peripheral blood CD3+T cell count apparently due to alterations of thymic T cell maturation, that can persist long term afterwards. Therefore, we analyzed the levels of peripheral blood TRECs (T-cell receptor excision circles), and investigated the main alterations in peripheral blood T cell subsets in COVID-19 convalescents. We performed molecular quantification of TRECs with “TREC/KREC-AMP PS” kit and flow cytometric analysis of peripheral blood lymphocytes from three groups of patients. The first group contained 109 samples from COVID-19 convalescents (6–12 month post-acute COVID-19) with normal levels of TRECs (TRECn); the second was formed from COVID-19 convalescents (6–12 month post-acute COVID-19) with decreased levels of TRECs (TREClow, n = 29), and healthy control group (HC, n = 18). We noticed no significant differences between all three groups in CD3+T cell relative and absolute numbers. However, CD4+T cell frequencies were decreased in TREClow and TRECn groups compared to HC (40.8% (31.6; 50.1) and 46.4% (40.0; 53.0) vs 53.5% (47.36; 56.9), p 0.001 and р = 0.004, respectively). Furthermore, Th cell levels were decreased in TREClow patients vs HC and TRECn groups (701 cell/1 µL (478; 807) vs 1005 cell/1 µL (700; 1419), р = 0.020, and 876 cell/ 1 µL (661; 1046), р = 0.008, respectively). Finally, both groups of COVID-19 convalescents had increased frequencies of circulating CD8+T cells — 29.4% (20.7; 39.7) in TREClow group, 26.5% (21.1; 32.7) in TRECn group vs 21.3% (17.1; 26.0) in healthy controls (p = 0.024 and р = 0.026, respectively). In TRECn group, CD8+T cell count was elevated vs control range (508 cell/1 µL (372; 622) vs 356 cell/1 µL (247; 531), р = 0.044). Thus, COVID-19 convalescents (6–12 month post-acute COVID-19) showed an imbalance in CD4+and CD8+T cell level even at 6–12 months post-acute SARS-CoV-2 infection, and the observed changes in peripheral blood T cells could be closely related to the alterations in thymic T cell maturation and differentiation. Such a long-term decline in TREC levels in the circulation may have a profound impact on immune system functions and requires immunocorrection therapy.

Enhanced platelet sensitization is accompanied by increased expression of the transporter MRP4 and elevated plasma S1P levels in mild COVID-19 convalescents

Viral infections can lead to platelet activation and hemostatic complications. However, the extent to which platelet reactivity remains altered after convalescence, contributing to long-term health impairments as observed after COVID-19 is not yet fully understood. Therefore, we conducted a cohort study (DRKS00025217) to determine platelet function in individuals convalesced from mild COVID-19. Assays were performed ex vivo with blood from convalescents at 2–15 weeks and 6–10 months after convalescence, focusing on platelet aggregation, activation markers, and thrombin formation. In addition, two other potentially relevant factors for platelet function were examined: the immunomodulatory mediator sphingosine-1-phosphate (S1P) and the platelet expression of the transporter MRP4 (ABCC4). Our findings indicate that robust platelet functions, including platelet aggregation determined by light transmission aggregometry, and thrombin formation, were not altered in convalescents compared to matched control individuals. However, an elevation in subtle platelet activation markers, such as P-selectin surface expression and activation of glycoprotein IIb/IIIa, was observed 2–15 weeks after convalescence. This was accompanied by an increased expression of MRP4 in platelets and significantly elevated levels of S1P in platelet-poor plasma. Our findings suggest increased platelet sensitization and a pro-inflammatory state even after convalescence from mild COVID-19, pointing toward MRP4 and S1P as associated factors.

Comparison οf Immune Responses Through Multiparametric T-Cell Cytokine Expression Profile Between Children with Convalescent COVID-19 or Multisystem Inflammatory Syndrome

Background/objectives: The immunological pathways that cause Multisystem Inflammatory Syndrome after SARS-CoV-2 infection in children (MIS-C) remain under investigation. Methods: The aim of this study was to prospectively compare the T-cell cytokine expression profile in unvaccinated children with acute MIS-C (MISC_A) before immunosuppression, convalescent MIS-C (one month after syndrome onset, MISC_C), convalescent COVID-19 (one month after hospitalization), and in healthy, unvaccinated controls. The intracellular expression of IL-4, IL-2, IL-17, IFNγ, TNF-α and Granzyme B, and the post SARS-CoV-2-Spike antigenic mix stimulation of T-cell subsets was analyzed by 13-color flow cytometry. Results: Twenty children with a median age (IQR) of 11.5 (7.25–14) years were included in the study. From the comparison of the flow cytometry analysis of the 14 markers of MISC_A with the other three groups (MISC_C, post-COVID-19 and controls), significant differences were identified as follows: 1. CD4+IL-17+/million CD3+: 293.0(256.4–870.9) vs. 50.7(8.4–140.5); p-value: 0.03, vs. 96.7(89.2–135.4); p-value: 0.03 and vs. 8.7(0.0–82.4); p-value: 0.03, respectively; 2. CD8+IL-17+/million CD3+: 335.2(225.8–429.9) vs. 78.0(31.9–128.9) vs. 84.1(0.0–204.6) vs. 33.2(0.0–114.6); p-value: 0.05, respectively; 3. CD8+IFNγ+/million CD3+: 162.2(91.6–273.4) vs. 41.5(0.0–77.4); p-value: 0.03 vs. 30.3(0.0–92.8); p-value: 0.08, respectively. Conclusions: In children presenting with MIS-C one month after COVID-19 infection, T cells were found to be polarized towards IL-17 and IFNγ production compared to those with uncomplicated convalescent COVID-19, a finding that could provide possible immunological biomarkers for MIS-C detection.

CD14 gene polymorphism in COVID-19 convalescents: analysis of (C-159)T

Cluster of differentiation 14 (CD14) is a pattern recognition receptor for lipopolysaccharide of gram-negative flora and has a close relationship with toll-like receptor 4 (TLR4). The interaction between CD14 and TLR 4 leads to the synthesis of cytokines such as interleukin-1, interleukin-6 and tumor necrosis factor-á. The TLR4 receptor is associated with the penetration of the new coronavirus infection virus into the cell, additionally stimulating the expression of the angiotensin converting enzyme 2 molecule and suppressing apoptosis in infected cells. Work on the study of the (159C)T polymorphism of the CD14 gene in COVID-19 is represented by only a few publications describing observations only in the Western European region. The purpose of our study was to study the association between single nucleotide polymorphism (SNP) of the CD14 gene – (159C)T (rs2569190) and susceptibility to a new coronavirus infection in the population of the Republic of Crimea. The study included 158 patients (87 women (55%) and 71 (45%) men, average age 45.6±6.14 years) who had COVID-19. Verification of previous COVID-19 was based on anamnestic data and data from studies performed at the time of illness (PCR). The control group consisted of 85 respondents who had not suffered a new coronavirus infection. To analyze the (C-159)T polymorphism of the CD14 gene, allele-specific PCR with electrophoretic detection in a 3% agarose gel (NPF "Litekh", Russia) was used. To compare the frequencies of allele combinations, the ÷2 test and odds ratio (95% CI) were used. The distribution of CD14 mutations followed Hardy-Weinberg equilibrium (p 0.05). The results of the study showed that the distribution of CD14 gene genotypes did not differ significantly in all study groups. The dominant genotype was the heterozygous genotype CT of the (C-159)T polymorphism of the CD14 gene. The analysis showed that the presence of CT and TT SNPs was not associated with the risk of developing a new coronavirus infection (p 0.05). Conclusions. The CD14 SNP (C-159)T is not associated with a higher risk of COVID-19 infection. The distribution of occurrence of SNP variants in the group of recovered individuals did not differ significantly from that in the control group (p 0.05).

Heterogeneity of SARS-CoV-2 immune responses after the nationwide Omicron wave in China.

It remains unclear how previous infections and vaccinations influenced and shaped heterogeneous immune responses against Omicron and its variants in diverse populations in China. After the national wave of Omicron in early 2023, we evaluated serum levels of neutralizing antibodies (nAbs) against Omicron (B.1.1.529) and its variants (BA.5, BF.7, and CH1.1) in 33 COVID-19 convalescents and 40 uninfected vaccinees, using vesicular stomatitis virus-based pseudovirus neutralizing assay. In addition, we followed 34 Delta convalescent patients to compare their immune responses against Omicron before (late 2021) and after the Omicron wave (early 2023). NAbs at the acute phase of the disease were investigated in 50 Omicron inpatients, including 24 vaccinated and 26 unvaccinated patients. Among them, nasal mucosal IgA levels were measured in 42 subjects. Compared to vaccination, breakthrough infections significantly increased the breadth and magnitude of serum nAbs and mucosal IgA levels against Omicron variants. Exposure to Omicron but not Delta elicited stronger pan-Omicron responses. In Omicron inpatients, nAbs continued to rise as vaccination doses increased. However, in both vaccinees and convalescents, a fourth dose vaccination did not elicit higher nAbs against Omicron. Furthermore, nAbs against Omicron variants lasted longer than nAbs against WT SARS-CoV-2. Breakthrough infections of Omicron variants elicited specific immune responses against Omicron compared to vaccination and Delta infection. Although repeated vaccination revealed limited impacts on serum nAbs, populations at high risk of hospitalization may still benefit from continued vaccination.IMPORTANCEThe study described the specific humoral immunity against Omicron and its variants (BA.5, BF.7, and CH1.1) in diverse populations, including Delta-positive convalescent patients, Omicron-infected patients with a previous or current confirmed Delta infection, Omicron-positive patients, and healthy controls. In addition, we followed Delta convalescents for 1 year to evaluate the effect of a booster vaccine, breakthrough infection, and reinfection. Nasal mucosal IgA levels against SARS-CoV-2 were also examined. The findings of this study demonstrated the varied responses of individuals in different states following the outbreak of Omicron, highlighting the potential advantages of ongoing immunization for groups that are more vulnerable and have a greater likelihood of being hospitalized.

Immunologic mediators profile in COVID-19 convalescence

SARS-CoV-2 caused the pandemic situation experienced since the beginning of 2020, and many countries faced the rapid spread and severe form of the disease. Mechanisms of interaction between the virus and the host were observed during acute phase, but few data are available when related to immunity dynamics in convalescents. We conducted a longitudinal study, with 51 healthy donors and 62 COVID-19 convalescent patients, which these had a 2-month follow-up after symptoms recovery. Venous blood sample was obtained from all participants to measure blood count, subpopulations of monocytes, lymphocytes, natural killer cells and dendritic cells. Serum was used to measure cytokines, chemokines, growth factors, anti-N IgG and anti-S IgG/IgM antibodies. Statistic was performed by Kruskal–Wallis test, and linear regression with days post symptoms and antibody titers. All analysis had confidence interval of 95%. Less than 35% of convalescents were anti-S IgM+, while more than 80% were IgG+ in D30. Anti-N IgG decreased along time, with loss of seroreactivity of 13%. Eosinophil count played a distinct role on both antibodies during all study, and the convalescence was orchestrated by higher neutrophil-to-lymphocyte ratio and IL-15, but initial stages were marked by increase in myeloid DCs, B1 lymphocytes, inflammatory and patrolling monocytes, G-CSF and IL-2. Later convalescence seemed to change to cytotoxicity mediated by T lymphocytes, plasmacytoid DCs, VEGF, IL-9 and CXCL10. Anti-S IgG antibodies showed the longest perseverance and may be a better option for diagnosis. The inflammatory pattern is yet present on initial stage of convalescence, but quickly shifts to a reparative dynamic. Meanwhile eosinophils seem to play a role on anti-N levels in convalescence, although may not be the major causative agent. We must highlight the importance of immunological markers on acute clinical outcomes, but their comprehension to potentialize adaptive system must be explored to improve immunizations and further preventive policies.

The Experience of Observational Departments’ Functioning for Treatment of Patients with Tuberculosis from COVID-19 Contact and Convalescents after COVID-19

Relevance. To control COVID-19, a net of special infection hospitals and departments was created, a system of medicaments and protective means’ supply was set up, necessary normative and regulatory documentation was developed and overall vaccination of population was performed in Moscow. Within frames of work for prophylaxis of COVID-19 spread in patients with tuberculosis at in-patient units of the State Budgetary Healthcare Institution of Moscow city «The Moscow Research and Clinical Center for Tuberculosis Control of the Moscow Government Department of Health” (hereinafter referred as the Center), observational departments for treatment of patients with tuberculosis from COVID-19 contact and convalescents after COVID-19. Aims. To evaluate specialized observational departments’ work as part of general anti-epidemic control measure system for COVID- 19 at tuberculosis hospitals. Materials and methods. The observational departments’ work within the period of 2020–2022 with 1075 patients treated including 400 patients from COVID-19 contact areas (37.2%) and 675 convalescent patients after COVID-19 (62.8%), was analyzed. The results obtained during the study were statistically treated by means of application program package Microsoft Office 2007. The quantitative parameters with presumably normal distribution were described with mean arithmetic values (M) and standard deviations (SD), and 95% confidence interval (CI 95%). The estimation of significance of differences between outcomes was evaluated with the Pearson χ2 test. The differences were considered to be statistically significant with p < 0,05. Results and discussion. The evaluation data on functioning efficacy of observational departments for patients with tuberculosis from COVID-19 contact and convalescent patients with tuberculosis after COVID-19 within the large medical institution hospital of physiatry profile. Among all patients, 153 of patients who fell ill with COVID-19 (14.2%; 95% CI [12.21–16.38%]) were determined, which lowered the number of COVID-19 areas at in-patient departments of the Center by 11.8%. The mean timeframes of COVID- 19 determination in general were 8.0 days: 5.4 days among contacts from new coronavirus infection areas and 12.4 days among convalescents at the department for the treatment of patients with tuberculosis and new coronavirus infection. The comparative analysis showed that COVID-19 was more frequently determined in tuberculosis patients from the contact with those who fell ill with COVID-19 (p < 0.001) than in convalescents. Conclusions. During medical care for patients of physiatry profile in Moscow city, a wide range of management decisions consisting in the change of routing system in specialized medical care, was taken. Among them, creation and functioning of observational departments for contact persons from COVID-19 areas and convalescents after COVID-19 play a particular role.Creation of such departments within a large medical institution enabled the contemporary isolation of contact persons from COVID- 19 areas and convalescents after COVID-19 and allowed the additional control of nosocomial infection spread

Safety and Immunogenicity of the Intranasal Vaccine Candidate Mambisa and the Intramuscular Vaccine Abdala Used as Booster Doses for COVID-19 Convalescents: A Randomized Phase 1-2 Clinical Trial.

A phase 1-2, prospective, multicenter, randomized, open-label clinical trial (Code RPCEC00000382), with parallel groups, involving 1161 participants, was designed to assess the safety and immunogenicity of two Cuban COVID-19 vaccines (Mambisa and Abdala) in boosting COVID-19 immunity of convalescent adults after receiving one dose of either vaccine. The main safety outcome was severe vaccination adverse events occurring in <5% of vaccinees. Main immunogenicity success endpoints were a ≥4-fold anti-RBD IgG seroconversion or a ≥20% increase in ACE2-RBD inhibitory antibodies in >55% of vaccinees in Phase 1 and >70% in Phase 2. Neutralizing antibody titers against SARS-CoV-2 variants were evaluated. Both vaccines were safe-no deaths or severe adverse events occurred. Mild intensity adverse events were the most frequent (>73%); headaches predominated for both vaccines. Phase 1 responders were 83.3% (p = 0.0018) for Abdala. Mambisa showed similar results. Phase 2 responders were 88.6% for Abdala (p < 0.0001) and 74.2% for Mambisa (p = 0.0412). In both phases, anti-RBD IgG titers, inhibition percentages and neutralizing antibody titers increased significantly after the booster dose. Both vaccines were safe and their immunogenicity surpassed the study endpoints.

Alterations in plasma proteome during acute COVID-19 and recovery

BackgroundThe severe course of COVID-19 causes cardiovascular injuries, although the mechanisms involved are still not fully recognized, linked, and understood. Their characterization is of great importance with the establishment of the conception of post-acute sequelae of COVID-19, referred to as long COVID, where blood clotting and endothelial abnormalities are believed to be the key pathomechanisms driving circulatory system impairment.MethodsThe presented study investigates temporal changes in plasma proteins in COVID-19 patients during hospitalization due to SARS-CoV-2 infection and six months after recovery by targeted SureQuant acquisition using PQ500 panel.ResultsIn total, we identified 167 proteins that were differentially regulated between follow-up and hospitalization, which functionally aggregated into immune system activation, complement and coagulation cascades, interleukins signalling, platelet activation, and extracellular matrix organization. Furthermore, we found that temporal quantitative changes in acute phase proteins correlate with selected clinical characteristics of COVID-19 patients.ConclusionsIn-depth targeted proteome investigation evidenced substantial changes in plasma protein composition of patients during and recovering from COVID-19, evidencing a wide range of functional pathways induced by SARS-CoV-2 infection. In addition, we show that a subset of acute phase proteins, clotting cascade regulators and lipoproteins could have clinical value as potential predictors of long-term cardiovascular events in COVID-19 convalescents.

Assessing molecular genetic and immunological predictors of COVID-19 course in healthcare worker risk group

Relevance. Studying features of innate and adaptive mechanisms of immune response in medical workers (MW), the most vulnerable social group with a high risk of infection, is an urgent research task. The aim of the study: Comprehensive study of innate and adaptive immune mechanisms and analyzing relationships between clinically significant polymorphisms (SNPs) in TLR2, TLR4 genes, TLR2 expression level on peripheral blood monocytes, peripheral blood cytokine profile (IL-1β, IL-10, IL-6, IFNγ, platelet activation marker) and SARS-CoV-2-specific humoral immune response in medical workers (MW) at a temporary infectious disease hospital in early and late COVID-19 convalescence. Materials and methods. immunologic, cytofluorimetric and molecular-genetic research methods were applied. Adaptive immune response in medical workers — COVID-19 convalescent subjects. Results. Early post-COVID-19 convalescence period in MW was linked to higher TLR2 monocyte expression; the mean fluorescence intensity was significantly elevated by 1.5-fold compared to control group. Late convalescence period (7 months post-COVID-19) was characterized by lowered serum IFNγ level. A decline in IFNγ production was significant: decreased by 82-fold in MR that was markedly stronger compared to control group (59 times). The imbalance of cytokines controlling antiviral innate and adaptive immune response was revealed in MW with identified combination of polymorphisms rs5743708 and rs4986790 in TLR2, TLR4 genes with the rate not exceeding 6.7%. It was found that 7 months after COVID-19 there was a markedly decreased IFNγ, IL-1β and IL-10 levels. The studies indicate both altered innate and adaptive immune mechanisms and a need to optimize therapeutic and prophylactic measures aimed at increasing patient-intrinsic resistance, protection of respiratory tract mucosal barriers and identification of genetic predictors of defects in innate and adaptive immune response in medical workers — COVID-19 convalescent subjects.

Severity of Postcovid Syndrome in Convalescent Covid-19 and Their Association with the Main Risk Factors for Chronic Non-Communicable Diseases

Severity of Postcovid Syndrome in Convalescent Covid-19 and Their Association with the Main Risk Factors for Chronic Non-Communicable Diseases

Single-cell transcriptomic analysis of B cells reveals new insights into atypical memory B cells in COVID-19.

Here, we performed single-cell RNA sequencing of S1 and receptor binding domain protein-specific B cells from convalescent COVID-19 patients with different clinical manifestations. This study aimed to evaluate the role and developmental pathway of atypical memory B cells (MBCs) in response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The results revealed a proinflammatory signature across B cell subsets associated with disease severity, as evidenced by the upregulation of genes such as GADD45B, MAP3K8, and NFKBIA in critical and severe individuals. Furthermore, the analysis of atypical MBCs suggested a developmental pathway similar to that of conventional MBCs through germinal centers, as indicated by the expression of several genes involved in germinal center processes, including CXCR4, CXCR5, BCL2, and MYC. Additionally, the upregulation of genes characteristic of the immune response in COVID-19, such as ZFP36 and DUSP1, suggested that the differentiation and activation of atypical MBCs may be influenced by exposure to SARS-CoV-2 and that these genes may contribute to the immune response for COVID-19 recovery. Our study contributes to a better understanding of atypical MBCs in COVID-19 and the role of other B cell subsets across different clinical manifestations.

Understanding the landscape of the SARS-CoV-2-specific T cells post-omicron surge.

Emerging evidence shows increased humoral response post-omicron surge, but research on T cell responses is limited. This study investigated the durability, magnitude, and breadth of SARS-CoV-2-spike-specific T cell responses in 216 two-dose vaccinated individuals pre- and post-omicron surge. Post-surge samples showed enhanced T cell responses, indicating widespread asymptomatic exposure to omicron. Further analysis of 105 individuals with multiple exposures to SARS-CoV-2 through boosters or infections showed that post-omicron, two-dose vaccinated individuals had T cell responses comparable to those of COVID-19 convalescents or boosted individuals. Additionally, we report cross-reactive T cell responses against omicron sub-variants, including BA2.86, remained strong, with preserved frequencies of spike-specific stem-cell-like memory T cells. In silico prediction indicates that mutated epitopes of JN.1 and KP.2 retain over 95.6% of their HLA binding capability. Overall, our data suggests that T cell responses are sustained, enhanced, and cross-reactive against emerging SARS-CoV-2 variants following symptomatic or asymptomatic omicron infection.

Recurrent spontaneous pneumothorax secondary to lung cystic lesions in a case of convalescent COVID-19: a case report and literature review

BackgroundWhile spontaneous pneumothorax has been documented in COVID-19 patients, reports on recurrent spontaneous pneumothorax due to cystic lesions in convalescent COVID-19 patients are scarce. The progression of these lung cystic lesions remains inadequately explored.Case presentation and literature reviewAn 81-year-old male, a non-smoker with a history of rheumatoid arthritis, presented with fever, cough, and expectoration for 14 days. Initially diagnosed with moderate COVID-19, he deteriorated to severe COVID-19 despite adherence to local treatment guidelines. Successive identification of three cystic lesions termed “bulla” or “pneumatocele”, and one cystic lesion with air-fluid level, referred to as “pneumo-hamatocele” (PHC), occurred in his lungs. Gradual improvement followed anti-inflammatory therapy and optimal supportive care. However, on day 42, sudden worsening dyspnea prompted a computed tomography (CT) scan, confirming a right spontaneous pneumothorax and subcutaneous emphysema, likely due to PHC rupture. Discharge followed chest tube implementation for pneumothorax resolution. On day 116, he returned to the hospital with mild exertional dyspnea. Chest CT revealed recurrent right pneumothorax from a remaining cyst in the right lung. Apart from our patient, literature retrieval identified 22 COVID-19 patients with spontaneous pneumothorax due to cystic lesions, with a male predominance (95.6%; 22/23). Diagnosis of pneumothorax and lung cystic lesions occurred around day 29.5 (range: 18–35) and day 26.4 (± 9.8) since symptom onset, respectively. Except for one patient whose pneumothorax occurred on day seven of illness, all patients eventually recovered.ConclusionsRecurrent spontaneous pneumothorax secondary to lung cystic lesions may manifest in convalescent COVID-19 patients, particularly males with COVID-19 pneumonia. Chest CT around 2 to 3 weeks post-symptom onset may be prudent to detect cystic lesion development and anticipate spontaneous pneumothorax.

Association between COVID-19 convalescent plasma antibody levels and COVID-19 outcomes stratified by clinical status at presentation

BackgroundThere is a need to understand the relationship between COVID-19 Convalescent Plasma (CCP) anti-SARS-CoV-2 IgG levels and clinical outcomes to optimize CCP use. This study aims to evaluate the relationship between recipient baseline clinical status, clinical outcomes, and CCP antibody levels.MethodsThe study analyzed data from the COMPILE study, a meta-analysis of pooled individual patient data from 8 randomized clinical trials (RCTs) assessing the efficacy of CCP vs. control, in adults hospitalized for COVID-19 who were not receiving mechanical ventilation at randomization. SARS-CoV-2 IgG levels, referred to as ‘dose’ of CCP treatment, were retrospectively measured in donor sera or the administered CCP, semi-quantitatively using the VITROS Anti-SARS-CoV-2 IgG chemiluminescent immunoassay (Ortho-Clinical Diagnostics) with a signal-to-cutoff ratio (S/Co). The association between CCP dose and outcomes was investigated, treating dose as either continuous or categorized (higher vs. lower vs. control), stratified by recipient oxygen supplementation status at presentation.ResultsA total of 1714 participants were included in the study, 1138 control- and 576 CCP-treated patients for whom donor CCP anti-SARS-CoV2 antibody levels were available from the COMPILE study. For participants not receiving oxygen supplementation at baseline, higher-dose CCP (/control) was associated with a reduced risk of ventilation or death at day 14 (OR = 0.19, 95% CrI: [0.02, 1.70], posterior probability Pr(OR < 1) = 0.93) and day 28 mortality (OR = 0.27 [0.02, 2.53], Pr(OR < 1) = 0.87), compared to lower-dose CCP (/control) (ventilation or death at day 14 OR = 0.79 [0.07, 6.87], Pr(OR < 1) = 0.58; and day 28 mortality OR = 1.11 [0.10, 10.49], Pr(OR < 1) = 0.46), exhibiting a consistently positive CCP dose effect on clinical outcomes. For participants receiving oxygen at baseline, the dose-outcome relationship was less clear, although a potential benefit for day 28 mortality was observed with higher-dose CCP (/control) (OR = 0.66 [0.36, 1.13], Pr(OR < 1) = 0.93) compared to lower-dose CCP (/control) (OR = 1.14 [0.73, 1.78], Pr(OR < 1) = 0.28).ConclusionHigher-dose CCP is associated with its effectiveness in patients not initially receiving oxygen supplementation, however, further research is needed to understand the interplay between CCP anti-SARS-CoV-2 IgG levels and clinical outcome in COVID-19 patients initially receiving oxygen supplementation.

Comparative Analysis of Lymphocyte Populations in Post-COVID-19 Condition and COVID-19 Convalescent Individuals.

Reduced lymphocyte counts in peripheral blood are one of the most common observations in acute phases of viral infections. Although many studies have already examined the impact of immune (dys)regulation during SARS-CoV-2 infection, there are still uncertainties about the long-term consequences for lymphocyte homeostasis. Furthermore, as persistent cellular aberrations have been described following other viral infections, patients with "Post-COVID-19 Condition" (PCC) may present similarly. In order to investigate cellular changes in the adaptive immune system, we performed a retrospective analysis of flow cytometric data from lymphocyte subpopulations in 106 patients with confirmed SARS-CoV-2 infection who received medical care at our institution. The patients were divided into three groups according to the follow-up date; laboratory analyses of COVID-19 patients were compared with 28 unexposed healthy controls. Regarding B lymphocyte subsets, levels of IgA + CD27+, IgG + CD27+, IgM + CD27- and switched B cells were significantly reduced at the last follow-up compared to unexposed healthy controls (UHC). Of the 106 COVID-19 patients, 56 were clinically classified as featuring PCC. Significant differences between PCC and COVID-19 convalescents compared to UHC were observed in T helper cells and class-switched B cells. However, we did not detect specific or long-lasting immune cellular changes in PCC compared to the non-post-COVID-19 condition.

The green spaces of the city and their significance in rehabilitation of cognitive functions – The spatial method of stimulation

The article addresses the spatial aspect as a factor of significant importance for the success of rehabilitation functions. The location of cognitive rehabilitation activities in an open, urban space allows people with reduced fitness to take up stress-free rehabilitation activity without time limitations and without stigmatization. The architectural design of the positions for mental rehabilitation implemented in public space was addressed to people with dysfunctions of all ages and people suffering from covid fog as a result of a past disease. This article presents the results of preliminary observational studies conducted on a focus group of COVID19 convalescents, who were provided with an open rehabilitation space equipped with 12 rehabilitation tables. The results showed the decisive influence of the placement of rehabilitation elements in the open green space for rehabilitation results. The task of the mind training path is to raise and maintain intellectual fitness in a friendly recreational space. Prototype studies have shown that, de-pending on the arrangement of individual stops, the mind training path offers different efficiency of exercises, but it is always a better result than in closed spaces of medical facilities.

Nonconserved epitopes dominate reverse preexisting T cell immunity in COVID-19 convalescents

The herd immunity against SARS-CoV-2 is continuously consolidated across the world during the ongoing pandemic. However, the potential function of the nonconserved epitopes in the reverse preexisting cross-reactivity induced by SARS-CoV-2 to other human coronaviruses is not well explored. In our research, we assessed T cell responses to both conserved and nonconserved peptides shared by SARS-CoV-2 and SARS-CoV, identifying cross-reactive CD8+ T cell epitopes using enzyme-linked immunospot and intracellular cytokine staining assays. Then, in vitro refolding and circular dichroism were performed to evaluate the thermal stability of the HLA/peptide complexes. Lastly, single-cell T cell receptor reservoir was analyzed based on tetramer staining. Here, we discovered that cross-reactive T cells targeting SARS-CoV were present in individuals who had recovered from COVID-19, and identified SARS-CoV-2 CD8+ T cell epitopes spanning the major structural antigens. T cell responses induced by the nonconserved peptides between SARS-CoV-2 and SARS-CoV were higher and played a dominant role in the cross-reactivity in COVID-19 convalescents. Cross-T cell reactivity was also observed within the identified series of CD8+ T cell epitopes. For representative immunodominant peptide pairs, although the HLA binding capacities for peptides from SARS-CoV-2 and SARS-CoV were similar, the TCR repertoires recognizing these peptides were distinct. Our results could provide beneficial information for the development of peptide-based universal vaccines against coronaviruses.

Reduced olfactory bulb volume accompanies olfactory dysfunction after mild SARS-CoV-2 infection

Despite its high prevalence, the determinants of smelling impairment in COVID-19 remain not fully understood. In this work, we aimed to examine the association between olfactory bulb volume and the clinical trajectory of COVID-19-related smelling impairment in a large-scale magnetic resonance imaging (MRI) analysis. Data of non-vaccinated COVID-19 convalescents recruited within the framework of the prospective Hamburg City Health Study COVID Program between March and December 2020 were analyzed. At baseline, 233 participants underwent MRI and neuropsychological testing as well as a structured questionnaire for olfactory function. Between March and April 2022, olfactory function was assessed at follow-up including quantitative olfactometric testing with Sniffin’ Sticks. This study included 233 individuals recovered from mainly mild to moderate SARS-CoV-2 infections. Longitudinal assessment demonstrated a declining prevalence of self-reported olfactory dysfunction from 67.1% at acute infection, 21.0% at baseline examination and 17.5% at follow-up. Participants with post-acute self-reported olfactory dysfunction had a significantly lower olfactory bulb volume at baseline than normally smelling individuals. Olfactory bulb volume at baseline predicted olfactometric scores at follow-up. Performance in neuropsychological testing was not significantly associated with the olfactory bulb volume. Our work demonstrates an association of long-term self-reported smelling dysfunction and olfactory bulb integrity in a sample of individuals recovered from mainly mild to moderate COVID-19. Collectively, our results highlight olfactory bulb volume as a surrogate marker that may inform diagnosis and guide rehabilitation strategies in COVID-19.

Quality of Life in Follow-Up up to 9 Months after COVID-19 Hospitalization among the Polish Population-A Prospective Single Center Study.

The consequences of COVID-19 constitute a significant burden to healthcare systems worldwide. Conducting an HRQoL assessment is an important aspect of the evaluation of the impact of the disease. The aim of this study was to investigate the prevalence of persistent symptoms and their impact on HRQoL and health status in COVID-19 convalescents. The study group consists of 46 patients who required hospitalization due to respiratory failure and who were subsequently evaluated 3 and 9 months after hospital discharge. At the follow-up visits, the patients were asked to assess their HRQoL using the EQ-5D-5L questionnaire. The results of chest CT, 6MWT, as well as the severity of the course of COVID-19 were also considered in the analysis. The obtained results have identified fatigue as the most common persistent symptom. The majority of the convalescents reported an impairment of HRQoL in at least one domain (80% and 82% after 3 and 9 months, respectively), of which the most common was that of pain/discomfort. The presence of ongoing symptoms may affect HRQoL in particular domains. The 6MWT outcome correlates with HRQoL 3 months after hospital discharge. Therefore, it may be useful in identifying patients with reduced HRQoL, allowing early interventions aimed at its improvement.