Are anti-SARS-CoV-2 S/N IgG/IgM antibodies always predictive of previous SARS-CoV-2 infection?

We planned this study to verify whether immunoassays for quantifying anti-SARS-CoV-2 IgG/IgM antibodies against both spike (S) and nucleocapsid (N) proteins may be used for identifying previous SARS-CoV-2 infections. The study population consisted of a cohort of fully vaccinated healthcare workers. All study subjects underwent regular medical visits and molecular testing for diagnosing SARS-CoV-2 infections every 2-4 weeks between 2020-2022. Venous blood was drawn for measuring anti-SARS-CoV-2 antibodies with MAGLUMI 2019-nCoV lgG/IgM CLIA Assays directed against both SARS-CoV-2 S and N proteins. Overall, 31/53 (58.5%) subjects had tested positive for SARS-CoV-2 by RT-PCR throughout the study (24 once, 7 twice). No positive correlation was found between anti-SARS-CoV-2 S/N IgM antibodies and molecular test positivity. In univariate regression analysis, both a molecular test positivity (r=0.33;p=0.015) and the number of positive molecular tests (r=0.43;p=0.001), but not vaccine doses (r=-0.12;p=0.392), were significantly correlated with anti-SARS-CoV-2 S/N IgG antibodies. These two associations remained significant in multiple linear regression analysis (p=0.029 and p<0.001, respectively) after adjusting for sex, age, body mass index, and vaccine doses. In ROC curve analysis, anti-SARS-CoV-2 S/N IgG antibodies significantly predicted molecular test positivity (AUC, 0.69;95% CI;0.55-0.84), with the best cutoff of 0.05 AU/mL displaying 67.9% accuracy, 0.97 sensitivity, and 0.27 specificity. Although anti-SARS-CoV-2 S/N IgG antibodies provide helpful information for identifying previous SARS-CoV-2 infections, a lower cutoff than that of sample reactivity should be used. Anti-SARS-CoV-2 S/N IgM antibodies using conventional cutoffs seem useless for this purpose. © 2023 the author(s), published by De Gruyter, Berlin/Boston.

D-dimer testing: A narrative review.

D-dimer containing species are soluble fibrin degradation products derived from plasmin-mediated degradation of cross-linked fibrin, i.e., 'D-dimer'. D-dimer can hence be considered a biomarker of in vivo activation of both coagulation and fibrinolysis, the leading clinical application in daily practice of which is ruling out venous thromboembolism (VTE). D-dimer has been further evaluated for assessing the risk of VTE recurrence and helping define optimal duration of anticoagulation treatment in VTE, for diagnosing disseminated intravascular coagulation (DIC), and for screening those at enhanced risk of VTE. D-dimer assays should however be performed as intended by regulatory agencies, as their use outside these indications might make them a laboratory-developed test (LDT). This narrative review is aimed at: (1) reviewing the definition of D-dimer, (2) discussing preanalytical variables affecting D-dimer measurement, (3) reviewing and comparing the assays performance and some postanalytical variables (e.g., different units and age-adjusted cutoffs), and (4) discussing the interest of D-dimer measurement across different clinical settings, including pregnancy, cancer, and coronavirus disease 2019 (COVID-19).

Could body temperature be used as surrogate measure of mRNA-based vaccination efficacy in the general population?

Predicting the humoral, cellular and clinical response to coronavirus disease 2019 (COVID-19) vaccination remains a central aspect for efficiently tackling the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Several current studies have focused on predicting the clinical response to COVID-19 vaccination by testing both immunological and cellular biomarkers. Nonetheless, this strategy is plagued by a number of drawbacks, so that a "biological marker" which may help predicting vaccine efficacy, efficiently surrogating laboratory-based tests, would be a valuable resource for optimizing vaccine delivery. A number of recent studies, summarized in this clinical practice review, have repeatedly emphasized the existence of a significant relationship between increased body temperature and humoral response after mRNA-based COVID-19 vaccination. Therefore, we put forward the idea that fever should be no longer considered only an adverse (almost undesirable) post-vaccination side effect, wherein its onset may actually reflect enhanced immunological response to vaccine, and its measurement could hence be used for screening at least mRNA-based vaccine immunogenicity in terms of humoral response up to 3 months after mRNA-based COVID-19 vaccination by using specifically validated algorithms incorporating the integrate assessment of body temperature and anti-SARS-CoV-2 antibodies.Copyright © Journal of Laboratory and Precision Medicine. All rights reserved.

The landscape of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomic mutations

Background: This article is aimed to provide an updated landscape of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomic mutations emerged since its first identification and sequencing. Method(s): We downloaded and analyzed all mutations within the SARS-CoV-2 RNA genome submitted up to February 8, 2022 to the website of the National Center for Biotechnology Information (NCBI), which contains all variants in Sequence Read Archive (SRA) records compared to the prototype SARS-CoV-2 reference sequence NC_045512.2. Result(s): Our search identified 26,005 different mutations. The largest number of mutations was located within the gene encoding for the Nsp3 protein (20.7%), followed by the gene encoding for the spike protein (14.6%). Overall, 17,948/26,005 (69.0%) of these mutations interested single nucleotide positions, thus spanning over ~62% of the entire SARS-CoV-2 genome. Of all mutations, 61.5% were non-synonymous, whilst 17.4% of those in the gene encoding for the spike protein involved the sequence of the receptor binding domain, 59.2% of which were non-synonymous. When the number of mutations was expressed as ratio to the gene size, the highest ratio was found in the sequence encoding for ORF7a (ratio, 2.25), followed by ORF7b (ratio, 1.85), ORF8 (ratio, 1.60) and ORF3a (ratio, 1.48). The gene encoding for RNA-dependent RNA polymerase accounted for only 0.1% of all mutations, with considerably low ratio with the gene size (i.e., ratio, 0.01). Conclusion(s): The results of our analysis demonstrate that SARS-CoV-2 has enormously mutated since its first sequence has been identified over 2 years ago.Copyright © 2022 AME Publishing Company. All rights reserved.

Longitudinal analysis of electrolyte prolife in intensive care COVID-19 patients

Introduction: According to a substantial body of research, electrolyte abnormalities are a common manifestation in coronavirus disease 2019 (COVID-19) patients and are associated with adverse outcomes. This study aimed to investigate electrolyte imbalances in COVID-19 patients and assess their relation to mortality. Method(s): Adult COVID-19 patients hospitalized in the Security Forces Hospital in Saudi Arabia from June 8th till August 18th, 2020 were enrolled in this retrospective observational study. We examined baseline characteristics, comorbidities, acute organ injuries, medications, and electrolyte levels including sodium, potassium, chloride, calcium, bicarbonate, phosphate, and magnesium on ICU admission, as well as every following day of ICU stay, until death or discharge. Patients were stratified according to survival, and differences in variables between groups were compared using Mann-Whitney's U test or Fisher's exact test. Longitudinal electrolyte profiles were modeled using random intercept linear regression models. Result(s): A total of 60 COVID-19 patients were enrolled. Compared to survivors, non-survivors had significantly higher sodium and phosphate on admission and death, higher potassium and magnesium at death, and significantly lower calcium at death. Abnormalities in admission levels of chloride and bicarbonate were also more frequently observed in non-survivors. Furthermore, in the deceased group, we observed a daily increase in potassium and phosphate levels, and a daily decrease in sodium and chloride. Finally, calcium increased in non-survivors over time, however, not as significantly as in the survivor group. Conclusion(s): Admission levels of electrolytes and changes over the course of ICU stay appear to be associated with mortality in COVID-19 patients.Copyright © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Altered lipid profile in patients with COVID-19 infection

Background: In this study, we aimed to investigate the pathological alterations of LDL-cholesterol, HDL-cholesterol, total cholesterol and triglycerides in COVID-19 patients during the acute phase of infection, and after recovery. Method(s): A retrospective study was performed to examine serum levels of LDL-cholesterol, HDL-cholesterol, total cholesterol and triglycerides on 55 COVID-19 patients who were hospitalized in our center between February and April 2020. The lipid profile and the hematological parameters were analyzed in the same group of patients before (Group before) and after clinical management (Group after). The laboratory tests results were compared between these two groups, as well as with a group of healthy subjects (Healthy controls), matched for age and sex and selected among the blood donors. Result(s): LDL-cholesterol, HDL-cholesterol, total cholesterol levels were significantly lower in COVID-19 patients (Group before) as compared with normal subjects (P<0.0001). Comparing healthy controls and the group after, statistically significant differences were observed for all parameters except for total cholesterol (P=0.9006). Total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride were found to be significantly higher after recovery than during the acute phase of infection (P<0.0001). C-reactive protein levels were found to be inversely correlated with those of LDL-cholesterol (rs =-0573, P<0.0001), total cholesterol (r=-0.732, P<0.0001), and HDL-cholesterol (r=-0.700, P<0.0001). Conclusion(s): The results of our study seemingly attest that lipids, especially cholesterol, may play an important role in viral replication, internalization and immune activation in patients with COVID-19 infection. Moreover, lipid abnormalities observed during and after this infection could be used for assessing indirectly the response to clinical treatment.Copyright © Journal of Laboratory and Precision Medicine. All rights reserved.

COVID-19 diagnostics and early phase clinical trials: challenges and risk mitigation in the Omicron variants era

The evolution of the coronavirus disease 2019 (COVID-19) pandemic and widespread community of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variants continues to present new challenges for early phase clinical trials and COVID-19 diagnostic strategies. Many regulatory agencies, including the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) continue to provide updated guidance on the operations of clinical trials during the pandemic. However, guidance is limited with respect to medical and scientific specific issues, such as COVID-19 diagnostics. Here we discuss, the challenges for early phase studies associated with COVID-19 diagnostics in the Omicron era and potential risk mitigation strategies in the face of continued widespread community transmission. We note how careful consideration and planning can help mitigating the risk of COVID-19 impacting the medical and scientific validity and patient safety in clinical trials. Clinical study design should consider mitigation strategies at the patient, investigator, and clinical research organization (CRO)/Sponsor level following evaluation of the overall for their specific study/investigational product and patient overall wellbeing. Specific language regarding COVID-19-related policies and procedures should be included in the study protocol. Special considerations should be taken for novel immunotherapeutics which may require interruption in the event of a subject developing COVID-19 or for investigative products that may have hazardous interactions with commonly prescribed anti-COVID-19 therapies. Moving forward, its essential for trials to remain adaptable to evolving nature of the pandemic. © Journal of Laboratory and Precision Medicine. All rights reserved.

Nationwide analysis of COVID-19 death rate throughout the pandemic in Italy

Background: No definitive epidemiological evidence is available on SARS-CoV-2 lethality during the surge of different variants of concern (VoCs) and coronavirus disease 2019 (COVID-19) vaccination in relation to common flu fatality. Methods: We collected and longitudinally analyzed official data about new COVID-19 cases and COVID-9 related deaths throughout the pandemic in Italy, which were then compared with the recent influenza virus-related fatality rate. Results: The mortality rate of COVID-19 has declined from 3.53% during predominance of the ancestral SARS-CoV-2 strain to 0.26–0.21% after surge of the new Omicron sublineages BA.1/2 and BA.4/5, when the nationwide COVID-19 vaccine coverage with primary cycle and booster doses has been concomitantly extended to 90.2% and 84.5% of the general population aged ≥12 years, respectively. The death rate of COVID-19 was approximately 11-fold higher than that of common flu (i.e., 3.53% versus 0.32%) at the beginning of the pandemic, but has then become 36% lower than that caused by the Influenza virus after widespread COVID-19 vaccine coverage, acquisition of natural immunity and surge of Omicron sublineages BA.4/5. Conclusions: Although our findings underpin a reassuring epidemiological scenario, with death rate of COVID-19 currently lower than that of Influenza virus in Italy, we reemphasize the importance of preventing further surge of aggressiveness (and potential lethality) of SARS-CoV-2, especially in the most vulnerable parts of the population. © Journal of Laboratory and Precision Medicine. All rights reserved.

Is limiting COVID-19 outside hospitals cost-effective? Cost-effectiveness analysis of the Italian special care continuity units (USCA)

Italian USCAs are composed of a team of specialists that visit COVID-19 patients at their homes so as to hospitalize promptly only the most serious cases. This paper was carried out on an USCA located in the surroundings of Florence, which operates on a vast hilly area of almost 60,000 inhabitants. The mean specific cost for each USCA patient is about 470(sic) and personnel cost alone is close to 90% of total direct specific costs. The Cost-Effectiveness Analysis developed in this article demonstrates that avoiding hospitalization of only 3% of USCA patients would be enough to offset the full cost of the USCA.

Clinical performance of Fujirebio Lumipulse G SARS-CoV-2 rapid antigen test

Introduction: SARS-CoV-2 infection has plagued the world for the past two years, during which time it has become necessary to use screening tests to prevent the spread of the virus, especially among high-risk patients. The gold standard for the detection of viral RNA is real-time PCR (RT-PCR). This technique requires special care when handling samples, as well as being time-consuming and costly. To meet the need for mass screening, antigenic tests were developed and continuously improved over the years. In our study, we examined the performance of Lumipulse G SARS-CoV-2 Ag (Fujirebio, Japan), a quantitative and automated chemiluminescence enzymeimmunoassay- based antigen test. Material(s) and Method(s): Our study includes 160 subjects (median age 38 years, interquartile range (IQR) 24-58 years;43% females) screened for SARS-COV-2 at the Service of Laboratory Medicine of Pederzoli Hospital (Peschiera del Garda, Verona, Italy), between August 16 and September 15, 2021. A nasopharyngeal swab was collected for each subject and analyzed at the same time by antigen test Fujirebio Lumipulse G SARS-CoV-2 Ag and by molecular test performed by Altona Diagnostics RealStar SARSCoV- 2 RT-PCR Kit (Altona Diagnostics GmbH, Hamburg, Germany). Result(s): A significant Spearman's correlation was found between values of Fujirebio Lumipulse G SARS-CoV-2 Ag and measurable Ct values of SARSCoV- 2 of both the S (r= -0.94;p<0.001) and E genes (r= -0.95;p<0.001). The sensitivity and specificity at 1.0 pg/ mL (cut-off already used by other authors to discriminate samples positive for SARS-CoV-2) were 0.71 and 1.00. We also used a locally calculated threshold of 0.60 pg/mL (sensitivity 0.88;specificity 0.75). The exclusion of samples tested positive at molecular testing with Ct values comprised between 25-37 enabled the attainment of better diagnostic performance on the 103 residual samples using the 0.60 pg/mL cut-off. Conclusion(s): the results of our study confirm the good performance of Fujirebio Lumipulse G SARS-CoV-2 Ag (considering cutoff 1.0 pg/mL), especially in samples with high viral load (i.e., Ct value <25), which has proved even better using our locally-calculated cut-off (i.e., 0.60 pg/mL).

Gammapatia Monoclonale E Infezione Da Sars-Cov-2

We report the clinical case of a 90-years-old woman with a history of arterial hypertension, hypothyroidism, obesity, and chronic obstructive pulmonary disease (COPD), who referred to our center (Pederzoli hospital, Peschiera del Garda, Verona, Italy) for dyspnea in January 2022 after tested positive for SARS-CoV-2 infection. The patient received primary vaccination with mRNA vaccine in October 2021. At the time of hospital admission, chest high resolution computed tomography (HRCT) revealed bilateral ground-glass opacities compatible with interstitial pneumonia. Blood tests revealed lymphopenia (0,7 10-3/ uL), iron (33 ug/dL) C-reactive protein (CRP) (28.1 mg/dL) and erythrocyte sedimentation rate (ESR) (79 mm). Treatment with oxygen therapy, steroids, and immunosuppressants (Baricitinib) was started. Two weeks after hospital discharge, during a routine examination, a totally unexpected alteration of the electrophoretic pattern was found on serum protein electrophoresis (SPEP) performed with Capillarys 2 (Sebia, Lisses, France). This alteration is visible as apeak in the g region and it was characterized as IgG-kappa by immunofixation performed with Hydrasys 2 (Sebia, Lisses, France). In this case, the unforeseen occurrence of such alteration in SPEP caught our attention because the patient had no previous evidence of monoclonal gammopathy, and her SPEP was normal in January 2022.A few studies describe the occurrence of a monoclonal spike in association with acute inflammatory illnesses, especially in viral infections. Considering that during severe COVID-19 there is a release of IL-6, which plays an important role in B-cells differentiation into plasma cells, a correlation could be hypothesized between the COVID 19 disease and the alteration in SPEP, without excluding the possible interference given by pharmacological therapy.In conclusion, our findings underline the need of further studies in order to evaluate the degree of immune hyperactivation in patients with severe COVID-19 and the prognostic role to improve the management of patients in this clinical setting.

Monitoraggio Della Risposta Anticorpale Al Vaccino

The immune response versus infective agents, thus including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), comprised the so-called adaptive immunity, which encompasses the generation of antibodies by B cells and cytotoxic activity by T cells, compounded by the immune memory, which has the role to contrast recurrent infections by the same pathogen. Serological testing has been conventionally defined as a diagnostic procedure used for detecting an immune response against an infectious agent, which can develop following either natural or artificial immunization. The crucial question that has emerged since the beginning of the worldwide COVID-19 vaccination campaign is whether or not laboratory monitoring of COVID-19 vaccination may be clinically useful and economically sustainable. Nonetheless, there are several reasons that contribute to justify the utility of serological monitoring after vaccination, including the opportunity (i) to know in advance whether vaccine recipients have passed a recent SARS-CoV-2 infection, (ii) to monitor the individual humoral response after vaccination, (iii) to verify the humoral response in presumably low-responder populations, and, last but not least, (iv) for timely detecting a fast decay of humoral protection [1]. According to the current knowledge, a timeline for serological testing could be suggested, entailing pre-vaccine measurement to precisely identify whether or not the subjects has been recently infected by SARS-CoV-2, followed by at least 2 following tests between 1 and 6 months to detect faster decline of anti-SARS-CoV-2 antibodies. As concerns the technical aspects, it may be advisable to use immunoassays capable to recognize antibodies targeting the entire trimeric spike protein, its S1 subunit, or its receptor binding domain, along with techniques that generate accurate quantitative values (1). Due to low degree of harmonization so far, an identical assay shall be used for longitudinal monitoring of antibodies values, and we finally advise against performing these measurements outside of clinical laboratories. That said, a major concern is rising. This is specifically due to the fact that the antigen and epitopes of the prototype SARS-CoV-2 lineage used for coating some immunoassays could no longer mirror the sequence of the spike protein or the RBD of some circulating variants, such as, for example, the highly mutated Omicron lineage. Contextually, the anti-SARS-CoV-2 antibodies elicited by these highly mutated SARS-CoV-2 lineages could be no longer reliably detected by some commercial immunoassays. Therefore, along with compulsory re-evaluation and revalidation of their methods against live virus neutralization assays, diagnostic companies must also embark in redesigning assays by replacing ancestral SARS-CoV-2 antigens with those of highly mutated SARS-CoV-2 variants (2).