BACKGROUND: Vaccination is one of the most effective medical interventions to prevent infectious diseases. The introduction of vaccines against coronavirus acute respiratory syndrome 2 (SARS-CoV-2) was aimed at preventing severe illness and death due to coronavirus disease 2019 (COVID-19). Solid organ transplant recipients (SOTRs) are at high risk of infection with SARS-CoV-2 and serious effects associated with COVID-19, mainly due to the use of immunosuppressive therapies, which further cause suboptimal response to COVID-19 vaccination.
OBJECTIVE: We aimed to compare post-vaccination response to BNT162b2 in kidney-pancreas transplant recipient, specifically in immunocompetent individuals, over two years of simultaneous monitoring.
METHODS: To determine the humoral response, the levels of the IgG and IgA anti-S1 antibodies were measured. To assess the cellular response to SARS-CoV-2, the released IFN-γ-S1 was determinate.
CONCLUSIONS: After primary vaccination, compared to immunocompetent subjects, SOTR showed lower seroconversion for both antibody classes. Only the additional dose produced antibodies at the level reached by the control group after the baseline vaccination. During the monitored period, SOTR did not achieve a positive cellular response in contrast to immunocompetent individuals, so in order to obtain longer protection, including immune memory, the adoption of booster doses of the vaccine should be considered.

BACKGROUND: The immunological background responsible for the severe course of COVID-19 and the immune factors that protect against SARS-CoV-2 infection are still unclear. The aim of this study was to investigate immune system status in persons with high exposure to SARS-CoV-2 infection.
METHODS: Seventy-one persons employed in the observation and infectious diseases unit were qualified for the study between November 2020 and October 2021. Symptomatic COVID-19 was diagnosed in 35 persons. Anti-SARS-CoV-2 antibodies were also found in 8 persons. Peripheral blood mononuclear cells subpopulations were analyzed by flow cytometry, and the concentrations of cytokines and anti-SARS-CoV-2 antibodies were determined by ELISA.
RESULTS: The percentages of cytotoxic T lymphocytes (CTLs), CD28+ and T helper (Th) cells with invariant T-cell receptors were significantly higher in persons with symptomatic COVID-19 than in those who did not develop COVID-19\' symptoms. Conversely, symptomatic COVID-19 persons had significantly lower percentages of: a) CTLs in the late stage of activation (CD8+/CD95+), b) NK cells, c) regulatory-like Th cells (CD4+/CTLA-4+), and d) Th17-like cells (CD4+/CD161+) compared to asymptomatic COVID-19\' persons. Additionally, persons with anti-SARS-CoV-2 antibodies had a significantly higher lymphocyte count and IL-6 concentration than persons without these antibodies.
CONCLUSIONS: Numerous lymphocyte populations are permanently altered by SARS-CoV-2 infection. High percentages of both populations: NK cells-as a part of the non-specific response, and T helper cells\' as those regulating the immune response, could protect against the acute COVID-19 symptoms development. Understanding the immune background of COVID-19 may improve the prevention of this disease by identifying people at risk of a severe course of infection.
BACKGROUND: This is a retrospective observational study without a trial registration number.

UNASSIGNED: At the beginning of the pandemic, COVID-19 convalescent plasma (CCP) containing anti-SARS-CoV-2 antibodies was suggested as a source of therapy. In the last 3 years, many trials have demonstrated the limited usefulness of CCP therapy. This led us to the hypothesis that CCP could contain other elements, along with the desired neutralizing antibodies, which could potentially prevent it from having a therapeutic effect, among them cytokines, chemokines, growth factors, clotting factors, and autoantibodies.
UNASSIGNED: In total, 39 cytokines were analyzed in the plasma of 190 blood donors, and further research focused on the levels of 23 different cytokines in CCP (sCD40L, eotaxin, FGF-2, FLT-3L, ractalkine, GRO-α, IFNα2, IL-1β, IL-1RA, IL-5, IL-6, IL-8, IL-12, IL-13, IL-15, IL-17E, IP-10, MCP-1, MIP-1b, PDGF-AA, TGFα, TNFα, and TRAIL). Anti-SARS-CoV-2 antibodies and neutralizing antibodies were detected in CCP.
UNASSIGNED: We found no significant differences between CCP taken within a maximum of 180 days from the onset of the first COVID-19 symptoms and the controls. We also made a comparison of the cytokine levels between the low neutralizing antibodies (<160) group and the high neutralizing antibodies (≥160) group and found there were no differences between the groups. Our research also showed no correlation either to levels of anti-SARS-CoV-2 IgG Ab or to the levels of neutralizing antibodies. There were also no significant changes in cytokine levels based on the period after the start of COVID-19 symptoms.
UNASSIGNED: No elements which could potentially be responsible for preventing CCP from having a therapeutic effect were found.

BACKGROUND: The aim of the rapid introduction of vaccines during the COVID-19 pandemic was a reduction in SARS-CoV-2 transmission and a less frequent occurrence of severe COVID-19 courses. Thus, we evaluated COVID-19 severity in vaccinated individuals to examine variant-specific symptom characteristics and their clinical impact on the serological immune response.
METHODS: A total of 185 individuals previously vaccinated against and infected with the SARS-CoV-2 Delta (B.1.617.2) or Omicron (BA.4 and BA.5) variant, were enrolled for anti-SARS-CoV-2 anti-N- and anti-RBD/S1-Ig level detection. A structured survey regarding medical history was conducted.
RESULTS: In 99.5 percent of cases, outpatient treatment was satisfactory. Specific symptoms associated with variants included ageusia and anosmia in patients with Delta infections and throat pain in Omicron infections. Among Delta-infected individuals with specific symptoms, significantly higher levels of anti-N antibodies were observed.
CONCLUSIONS: Our study identified variant-specific differences in the amount of SARS-CoV-2 antibody production and COVID-19 symptoms. Despite this, vaccinated individuals with Omicron or Delta infections generally experienced mild disease courses. Additionally, asymptomatic individuals exhibit lower anti-SARS-CoV-2 antibody levels, indicating a clinical correlation between disease-specific antibodies and distinct symptoms, particularly in the case of the Delta variant. In follow-up studies, exploring post-COVID syndrome and focusing on cognitive symptoms in the acute phase of Omicron infections is crucial as it has the potential to longitudinally impact the lives of those affected.

OBJECTIVE: Globally, over 772 million cases of COVID-19 have been reported. New variants of interest with corresponding spikes in case numbers continue to be identified. Vulnerable patients, including older adults or patients with severe comorbidities, continue to be at risk. A large body of evidence has been accumulated regarding anti-SARS-CoV-2-antibodies and COVID-19 but the usefulness of antibody measurements remains unclear. This systematic review aims to assess the prognostic value of anti-SARS-CoV-2-antibodies and their usefulness for guiding booster vaccinations.
METHODS: Studies in English and published between January 2020 and October 2023 were included. Studies that relied on multiparameter-models or comprised fewer than 100 participants were excluded. PubMed and via the WHO COVID-19 research database, Embase and Medline databases were searched. Study selection and quality assessment was conducted independently by two researchers.
RESULTS: After screening 1,160 studies, 33 studies comprising >30 million individuals were included. Anti-SARS-CoV-2-antibodies were strongly associated with reduced risk of SARS-CoV-2-infection and better outcomes, including mortality. Risk of infection and COVID-19 severity decreased with increasing antibody levels.
CONCLUSIONS: Anti-SARS-CoV-2-antibodies are useful for early identification of high-risk patients and timely adjustment of therapy. Protective thresholds may be applied to advise booster vaccinations but verification in separate cohorts is required.

Since the onset of the COVID-19 pandemic in March 2020, over 769 million confirmed COVID-19 cases, including close to 7 million COVID-19-related deaths, have been reported. Although mortality rates have dropped notably compared to the first months of the pandemic, spikes in reported cases and mortality rates continue to be registered. Both recent spikes in case numbers and the continued emergence of new variants suggest that vulnerable patient groups, including older adults, immunocompromised patients, and patients with severe comorbidities, are going to continue to be affected by COVID-19. In order to curb the pandemic, relieve the pressure on primary care facilities, and reduce mortality rates, global vaccination programs have been established by the WHO, with over 13.5 billion vaccine doses having been administered globally. In most immunocompetent individuals, vaccination against COVID-19 results in the production of anti-SARS-CoV-2 spike antibodies. However, certain patient subsets have inadequate or reduced immune responses, and immune responses are known to decrease with age. General recommendations on the timing of booster vaccinations may therefore be insufficient to protect vulnerable patients. This review aims to evaluate the clinical role of anti-SARS-CoV-2 antibodies, focusing on measurement indications, prognostic value, and potential as a correlate of protection to guide future booster vaccination strategies.

OBJECTIVE: We have previously highlighted the fact that hundreds of SARS-CoV-2 serology tests were released months after the onset of the COVID-19 pandemic. Of the hundreds of studies investigating the test kits\' performance, few were comparative reports, using the same comprehensive sample set across multiple tests. Recently, we reported a comparative assessment of 35 rapid diagnostic tests (RDTs) or microtiter plate enzyme immunoassays (EIA) for use in low- and middle-income countries, using a large sample set from individuals with a history of COVID-19. Only a few tests meet WHO Target Product Profile performance requirements. This study reports on the performance of a further 25 automated SARS-CoV-2 immunoassays using the same panel of samples. The results highlight the better analytical and clinical performance of automated serology test kits compared with RDTs, and the importance of independent comparative assessments to inform the use and procurement of these tests for both diagnostic and epidemiological investigations.

OBJECTIVE: The assessment of the prevalence of anti-SARS-CoV-2 antibodies in various professional groups is very important. Hence, the purpose of the following study was to analyze the seroprevalence of anti-SARS-CoV-2 antibodies among employees performing both medical and nonmedical professions before the launch of SARS-CoV-2 vaccination.
METHODS: The study was conducted among employers of 1 of the institutions: The Provincial Specialist Hospital of Władysław Biegański in Łódź, Poland, Radio Łódź and the Border Guards of Łódź Airport. Blood samples were collected in December 2020-February 2021. Patients were screened for the presence of SARS-CoV-2 antibodies. Simultaneously respondents were asked to complete a self-designed questionnaire including demographic data, detailed profession, history of SARS-CoV-2 infection and willingness to be vaccinated against COVID-19.
RESULTS: Seroprevalence was significantly higher in the group of rural residents (p < 0.012), participants who declared previous COVID-19 infection (p < 0.001) and healthcare workers (HCWs) (p = 0.002), especially nurses (35.5%, p = 0.003) and medics worked in areas dedicated to COVID-19 than in other specialties (38.7% vs. 26.8%, respectively, p = 0.017). There was no association between the presence of antibodies and the gender (p = 0.118), age (p = 0.559) or BMI (p = 0.998).
CONCLUSIONS: Healthcare workers, in particular nurses, are at high risk of contracting COVID-19 in the workplace. Occupational infections can occur during occur not only during contact with the patient, but also with members of the medical team who do not show typical symptoms of the disease. Shortages in medical staff may also increase the number of infections among HCWs. Medical and hospital staff providing health services during the COVID-19 epidemic in Poland, may seek compensation in the event of consequences related to SARS-CoV-2 infection. The effectiveness of education and self-discipline in complying to safety rules among HCWs should also be constantly monitored. Int J Occup Med Environ Health. 2023;36(5):643-55.

BACKGROUND: The emergence of SARS-CoV-2 becomes life-threatening for the older and immunocompromised individuals, whereas limited treatment is available on these populations. Mesenchymal stromal cells (MSCs) have been reported to be useful in SARS-CoV-2 treatment and reduce SARS-CoV-2-related sequelae.
RESULTS: In this study, we developed an autonomous cellular machine to secret neutralizing antibody in vivo constantly based on the clinical-grade MSCs, to combat SARS-CoV-2 infections. First, various modified recombinant plasmids were constructed and transfected into clinical-grade MSCs by electroporation, for assembly and expression of neutralizing anti-SARS-CoV-2 antibodies. Second, the stable antibody secreting MSCs clones were screened through pseudovirus neutralization assay. Finally, we investigated the pharmacokinetics and biodistribution of neutralizing antibody secreted by engineered MSCs in vivo. The stable clinical-grade MSCs clones, expressing XGv347-10 and LY-CoV1404-5 neutralizing antibodies, exhibited their feasibility and protective efficacy against SARS-CoV-2 infection. Transplanted engineered clinical-grade MSCs effectively delivered the SARS-CoV-2 antibodies to the lung, and the immune hyperresponsiveness caused by COVID-19 was coordinated by MSC clones through inhibiting the differentiation of CD4 + T cells into Th1 and Th17 subpopulations.
CONCLUSIONS: Our data suggested that engineered clinical-grade MSCs secreting effective neutralizing antibodies as cellular production machines had the potential to combat SARS-CoV-2 infection, which provided a new avenue for effectively treating the older and immunocompromised COVID-19 patients.

BACKGROUND: Recent studies suggest that both lipid levels and anti-severe-acute-respiratory-syndrome-coronavirus-2 (SARS-CoV-2) antibody levels are associated with outcome in coronavirus disease 2019 (COVID-19). While both parameters have separately been implicated in the neutralization and clearance of pathogens during severe infections, it is currently unclear whether the interplay of these parameters affects outcome in COVID-19. We therefore aimed to determine whether there was a relationship between lipoproteins, anti-SARS-CoV-2 antibodies, and COVID-19 mortality.
METHODS: In this prospective, multicenter cohort study, we recruited 1152 hospitalized patients with COVID-19 from five hospitals. Total cholesterol (TC), LDL-C, HDL-C, triglycerides, and anti-SARS-CoV-2 spike antibodies were measured on hospital admission. The investigated endpoint was in-hospital mortality.
RESULTS: LDL-C, HDL-C, and TC were significantly lower in non-survivors than in survivors (mg/dL, 95%CI; 56.1, 50.4-61.8 vs. 72.6, 70.2-75.0, p < 0.001; 34.2, 31.7-36.8 vs. 38.1, 37.2-39.1, p = 0.025; 139.3, 130.9-147.7 vs. 157.4, 54.1-160.6, p = 0.002). Mortality risk increased progressively with lower levels of LDL-C, HDL-C, and TC (aOR 1.73, 1.30-2.31, p < 0.001; 1.44, 1.10-1.88, p = 0.008; 1.49, 1.14-1.94, p < 0.001). Mortality rates varied between 2.1% for high levels of both LDL-C and anti-SARS-CoV-2 antibodies and 16.3% for low levels of LDL-C and anti-SARS-CoV-2 antibodies (aOR 9.14, 95%CI 3.17-26.34, p < 0.001). Accordingly, for total cholesterol and anti-SARS-CoV-2 antibodies, mortality rates varied between 2.1% and 15.0% (aOR 8.01, 95%CI 2.77-23.18, p < 0.001).
CONCLUSIONS: The combination of serum lipid levels and anti-SARS-CoV-2 antibodies is strongly associated with in-hospital mortality of patients with COVID-19. Patients with low levels of LDL-C and total cholesterol combined with low levels of anti-SARS-CoV-2 antibodies exhibited the highest mortality rates.