Tixagevimab/Cilgavimab: Still a Valid Prophylaxis against COVID-19 New Variants?

BACKGROUND: this study aims to evaluate the efficacy of tixagevimab/cilgavimab (Evusheld™) against various SARS-CoV-2 variants, including newer Omicron sublineages, in an immunocompromised cohort and in vitro. STUDY DESIGN: Conducted in Italy, this research involves immunocompromised patients who received Evusheld. It evaluates serum neutralization activity against different SARS-CoV-2 strains (20A.EU1, BA.5, BQ.1, XBB.1.5, XBB.1.16, and EG.5) before (T0), after 14 (T1), and after 30 (T2) days from the tixagevimab/cilgavimab injection. Furthermore, the in vitro activity of Evusheld against SARS-CoV-2 VOCs was evaluated. RESULTS: The cohort was composed of 72 immunocompromised patients. The serum neutralizing activity of tixagevimab/cilgavimab-treated patients was notably lower against newer variants such as BQ.1, XBB.1.5, XBB.1.16, and EG.5. Then, the in vitro study detailed specific EC50 values to quantify the activity of tixagevimab/cilgavimab against various SARS-CoV-2 VOCs. Newer variants like BQ.1 and XBB.1.5 exhibited notably lower neutralization, underscoring the challenges in effectively countering the evolving virus. Interestingly, tixagevimab/cilgavimab maintained reduced but still valid activity against EG.5 with an EC50 of 189 ng/mL and Cmax/EC90 of 110.7. CONCLUSIONS: Tixagevimab/cilgavimab efficacy wanes against novel subvariants. This underscores the critical need for ongoing adaptation and vigilance in prophylactic strategies to effectively counter the dynamic and unpredictable nature of the COVID-19 pandemic.

In-label, off-label prescription, efficacy and tolerability of dalbavancin: report from a National Registry.

PURPOSE: Although dalbavancin is currently approved for the treatment of ABSSIs, several studies suggest its efficacy and tolerance as long-term therapy for other off-label indications requiring prolonged intravenous antibiotic administration. METHODS: We conducted a prospective nationwide study of dalbavancin use in real-life settings for both approved and off-label indications analysing for each case the clinical and microbiological characteristics of infection the efficacy and safety of treatments. RESULTS: During the study period (from December 2018 to July 2021), the ID specialists from 14 different centres enrolled 223 patients treated with dalbavancin [141 males (63%) and 82 females (37%); male/female ratio 1.72; mean age 59 (SD 17.2) years, (range 15-96). Most patients in the study population (136/223; 61.0%) came from community rather than health care facilities and most of them were visited in Infectious Diseases wards (93/223; 41.7%) and clinics (55/223; 24.7%) even though some patients were cured in other settings, such as surgery wards (18/223; 8.1%), orthopaedic wards (11/223; 4.9%), Emergency Rooms (7/223; 3.1%) and non-surgical other than ID wards (6/223; 2.7%). The most common ID diagnoses were osteomyelitis (44 cases/223; 19.7%; of which 29 acute and 15 chronic osteomyelitis), cellulitis (28/223; 12.5%), cutaneous abscess (23/223; 10.3%), orthopaedic prosthesis-associated infection (22/223; 9.9%), surgical site infection (20/223; 9.0%) and septic arthritis (15/223; 6.7%). CONCLUSION: In conclusion, by virtue of its PK/PD properties, dalbavancin represents a valuable option to daily in-hospital intravenous or outpatient antimicrobial regimens also for off-label indications requiring a long-term treatment of Gram-positive infections.

Bictegravir/Tenofovir Alafenamide/Emtricitabine: A Real-Life Experience in People Living with HIV (PLWH).

BACKGROUND: Bictegravir (BIC), a recently introduced integrase inhibitor, is available in a single tablet regimen with tenofovir alafenamide (TAF) and emtricitabine (FTC) (BIC-STR). This study aimed to describe a real-life experience with BIC-STR. METHODS: We retrospectively analyzed the data of people living with HIV (PLWH) on antiretroviral therapy (ART) with BIC-STR followed by the Clinic of Infectious Diseases of Perugia (Perugia, Italy) from September 2019 to February 2023. RESULTS: 270 PLWH were enrolled with a median follow-up time on BIC-STR of 2.2 years (IQR 1.2-2.7). In the overall population, in treatment-experienced (N = 242), in treatment-naïve (N = 28), and in population with age > 60 years old (N = 86), we observed that CD4 cell count improved in absolute number, percentage and CD4/CD8 ratio, under BIC-STR. Patients with viremia < 50 cp/mL increased in all groups. In the overall population, previous ART with TAF and nadir CD4 cell count favored immunological recovery. In the ART-experienced group, time in therapy with BIC-STR was associated with HIV-RNA undetectability. In the older group, previous opportunistic infection and advanced age were associated with lower CD4 count. CONCLUSIONS: BIC-STR was demonstrated, in real-life, to be a valid option for a switch, such as initial ART.

Impaired neutralizing antibody efficacy of tixagevimab-cilgavimab 150+150 mg as pre-exposure prophylaxis against Omicron BA.5. A real-world experience in booster vaccinated immunocompromised patients.

BACKGROUND: Tixagevimab-cilgavimab has been approved as primary pre-exposure prophylaxis in immunocompromised patients as support or replacement for vaccination, even though the Omicron variant of concern (VOC) was spreading at the time. OBJECTIVES: The aim of our study was to evaluate the post-injection neutralising activity (NT90-Abs titre) against the Omicron BA.5 variant in fully vaccinated immunocompromised patients. STUDY DESIGN: NT90-Abs titres against BA.5 and 20A.EU1 as well as anti-spike and anti-receptor-binding domain IgG were evaluated 0, 14, and 30 d after tixagevimab-cilgavimab administration. The primary end point was NT90-Abs titres ≥ 80 against BA.5 in ≥ 25% of patients, and the secondary end point was NT90-Abs titres ≥ 1280 against 20A.EU1 in >50% of patients on day 14. RESULTS: At baseline, 35.2%, 37.02%, and 32.5% of booster vaccinated patients exhibited undetectable levels of anti-S and anti-RBD IgG antibodies such as NT90-Abs titres against A20.EU1. Moreover, 35 patients (61.5%) had undetectable NT90-Abs titres against BA.5. On day 14, IgG anti-S and anti-RBD levels were 3880 BAU/mL and 776.6 AU/mL, respectively. Only 12.5% of patients met a NT90-Abs titres ≥ 80 against BA.5, whereas the median NT90-Abs titre against 20A.EU1 was 1280. NT90-Abs titres against BA.5 were 64-fold lower than those against A20.EU1. Four patients (7.5%) had a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the 3 months after treatment, all with a time gap between the booster vaccination and injection. CONCLUSIONS: To date, tixagevimab-cilgavimab cannot be considered a substitute for vaccination but may be a useful supporting therapy if the recommended dose for pre-exposure prophylaxis is doubled.

The hope and hype of ellagic acid and urolithins as ligands of SARS-CoV-2 Nsp5 and inhibitors of viral replication.

Non-structural protein 5 (Nsp5) is a cysteine protease that plays a key role in SARS-CoV-2 replication, suppressing host protein synthesis and promoting immune evasion. The investigation of natural products as a potential strategy for Nsp5 inhibition is gaining attention as a means of developing antiviral agents. In this work, we have investigated the physicochemical properties and structure-activity relationships of ellagic acid and its gut metabolites, urolithins A-D, as ligands of Nsp5. Results allow us to identify urolithin D as promising ligand of Nsp5, with a dissociation constant in the nanomolar range of potency. Although urolithin D is able to bind to the catalytic cleft of Nsp5, the appraisal of its viral replication inhibition against SARS-CoV-2 in Vero E6 assay highlights a lack of activity. While these results are discussed in the framework of the available literature reporting conflicting data on polyphenol antiviral activity, they provide new clues for natural products as potential viral protease inhibitors.

Synergistic Activity of Remdesivir-Nirmatrelvir Combination on a SARS-CoV-2 In Vitro Model and a Case Report.

BACKGROUND: This study aims to investigate the activity of the remdesivir-nirmatrelvir combination against Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) and to report a case of Coronavirus Disease 2019 (COVID-19) cured with this combination. METHODS: A Vero E6 cell-based infection assay was used to investigate the in vitro activity of the remdesivir-nirmatrelvir combination. The SARS-CoV-2 strains tested were 20A.EU1, BA.1 and BA.5. After incubation, a viability assay was performed. The supernatants were collected and used for viral titration. The Highest Single Agent (HSA) reference model was calculated. An HSA score >10 is considered synergic. RESULTS: Remdesivir and nirmatrelvir showed synergistic activity at 48 and 72 h, with an HSA score of 52.8 and 28.6, respectively (p < 0.0001). These data were confirmed by performing supernatant titration and against the omicron variants: the combination reduced the viral titer better than the more active compound alone. An immunocompromised patient with prolonged and critical COVID-19 was successfully treated with remdesivir, nirmatrelvir/ritonavir, tixagevimab/cilgavimab and dexamethasone, with an excellent clinical-radiological response. However, she required further off-label prolonged therapy with nirmatrelvir/ritonavir until she tested negative. CONCLUSIONS: Remdesivir-nirmatrelvir combination has synergic activity in vitro. This combination may have a role in immunosuppressed patients with severe COVID-19 and prolonged viral shedding.

Stabilization of the Dimeric State of SARS-CoV-2 Main Protease by GC376 and Nirmatrelvir.

The main protease (Mpro or 3CLpro) is an enzyme that is evolutionarily conserved among different genera of coronaviruses. As it is essential for processing and maturing viral polyproteins, Mpro has been identified as a promising target for the development of broad-spectrum drugs against coronaviruses. Like SARS-CoV and MERS-CoV, the mature and active form of SARS-CoV-2 Mpro is a dimer composed of identical subunits, each with a single active site. Individual monomers, however, have very low or no catalytic activity. As such, inhibition of Mpro can be achieved by molecules that target the substrate binding pocket to block catalytic activity or target the dimerization process. In this study, we investigated GC376, a transition-state analog inhibitor of the main protease of feline infectious peritonitis coronavirus, and Nirmatrelvir (NMV), an oral, bioavailable SARS-CoV-2 Mpro inhibitor with pan-human coronavirus antiviral activity. Our results show that both GC376 and NMV are capable of strongly binding to SARS-CoV-2 Mpro and altering the monomer-dimer equilibrium by stabilizing the dimeric state. This behavior is proposed to be related to a structured hydrogen-bond network established at the Mpro active site, where hydrogen bonds between Ser1' and Glu166/Phe140 are formed in addition to those achieved by the latter residues with GC376 or NMV.

Nelfinavir: An Old Ally in the COVID-19 Fight?

After almost three years of the pandemic, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is still spreading around the world, causing notable sanitary and social issues. New antiviral therapies are constantly under investigation. However, few options have been approved for the treatment of COVID-19. Clinical trials are currently ongoing to evaluate the efficacy of nelfinavir on mild−moderate COVID-19. This study aims to investigate the activity of this compound on SARS-CoV-2 "Variants of Concern" (VOCs), comparing its effectiveness with the approved drugs remdesivir and molnupiravir. The experiments were conducted in a biosafety level 3 facility. In this study, we used a Vero-E6-cell-based infection assay to investigate the in vitro activity of nelfinavir, molnupiravir, and remdesivir. Four strains of SARS-CoV-2 were tested: 20A.EU1, B.1.1.7, P.1, and B.1.617.2. All compounds reached micromolar/submicromolar EC50, EC90, and EC99. Furthermore, the Cmax/EC50 and Cmax/EC90 ratios were >1 for all compounds and all variants tested. Our study demonstrated that nelfinavir, as molnupiravir, and remdesivir are effective in vitro on SARS-CoV-2 variants.

BNT162b2 Elicited an Efficient Humoral Response Against Different Strains of SARS-CoV-2 in People Living with HIV.

BACKGROUND: Vaccines have had a fundamental impact in containing the ongoing Coronavirus Disease 2019 (COVID-19) pandemic. However, there are few efficacy data relating to frail patients, including the HIV-positive patient. OBJECTIVE: This study evaluated the Severe Acute Respiratory Syndrome Coronavirus 2 (SARSCoV- 2) serum neutralization in People Living with HIV (PLWH) compared to a cohort of healthy volunteers both vaccinated with BNT162b2. METHODS: A serum sample was then withdrawn 14-21 days after the second dose of the vaccine and a serum neutralization assay was performed on Vero E6 cells. The experiments were performed using two strains of SARS-CoV-2 as 20A.EU1 and B.1.617.2. RESULTS: PLWH on Antiretroviral Therapy (ART) showed a vaccine response comparable to the healthy subjects. No correlation between CD4 count or CD4/CD8 and neutralizing antibodies (NTAbs) has been found. No differences in NT-Abs between patients with CD4 nadir above or under 200 cells/µl have been found. In both cohorts, vaccine-elicited serum better neutralized 20A.EU1 than B.1.617.2 strain. CONCLUSION: PLWH in ART and with good immuno-virological recovery showed a vaccine response comparable to that of healthy subjects and regardless of their immunological status at HIV infection diagnosis. However, larger studies are needed to confirm our results and to evaluate the vaccine response even in patients with low CD4 counts.

Efficacy of Licensed Monoclonal Antibodies and Antiviral Agents against the SARS-CoV-2 Omicron Sublineages BA.1 and BA.2.

Newly emerging SARS-CoV-2 variants may escape monoclonal antibodies (mAbs) and antiviral drugs. By using live virus assays, we assessed the ex vivo inhibition of the B.1 wild-type (WT), delta and omicron BA.1 and BA.2 lineages by post-infusion sera from 40 individuals treated with bamlanivimab/etesevimab (BAM/ETE), casirivimab/imdevimab (CAS/IMD), and sotrovimab (SOT) as well as the activity of remdesivir, nirmatrelvir and molnupiravir. mAbs and drug activity were defined as the serum dilution (ID50) and drug concentration (IC50), respectively, showing 50% protection of virus-induced cytopathic effect. All pre-infusion sera were negative for SARS-CoV-2 neutralizing activity. BAM/ETE, CAS/IMD, and SOT showed activity against the WT (ID50 6295 (4355-8075) for BAM/ETE; 18,214 (16,248-21,365) for CAS/IMD; and 456 (265-592) for SOT) and the delta (14,780 (ID50 10,905-21,020) for BAM/ETE; 63,937 (47,211-79,971) for CAS/IMD; and 1103 (843-1334) for SOT). Notably, only SOT was active against BA.1 (ID50 200 (37-233)), whereas BA.2 was neutralized by CAS/IMD (ID50 174 (134-209) ID50) and SOT (ID50 20 (9-31) ID50), but not by BAM/ETE. No significant inter-variant IC50 differences were observed for molnupiravir (1.5 ± 0.1/1.5 ± 0.7/1.0 ± 0.5/0.8 ± 0.01 µM for WT/delta/BA.1/BA.2, respectively), nirmatrelvir (0.05 ± 0.02/0.06 ± 0.01/0.04 ± 0.02/0.04 ± 0.01 µM) or remdesivir (0.08 ± 0.04/0.11 ± 0.08/0.05 ± 0.04/0.08 ± 0.01 µM). Continued evolution of SARS-CoV-2 requires updating the mAbs arsenal, although antivirals have so far remained unaffected.

The Combination of Molnupiravir with Nirmatrelvir or GC376 Has a Synergic Role in the Inhibition of SARS-CoV-2 Replication In Vitro.

Introduction: The development of effective vaccines has partially mitigated the trend of the SARS-CoV-2 pandemic; however, the need for orally administered antiviral drugs persists. This study aims to investigate the activity of molnupiravir in combination with nirmatrelvir or GC376 on SARS-CoV-2 to verify the synergistic effect. Methods: The SARS-CoV-2 strains 20A.EU, BA.1 and BA.2 were used to infect Vero E6 in presence of antiviral compounds alone or in combinations using five two-fold serial dilution of compound concentrations ≤EC90. After 48 and 72 h post-infection, viability was performed using MTT reduction assay. Supernatants were collected for plaque-assay titration. All experiments were performed in triplicate, each being repeated at least three times. The synergistic score was calculated using Synergy Finder version 2. Results: All compounds reached micromolar EC90. Molnupiravir and GC376 showed a synergistic activity at 48 h with an HSA score of 19.33 (p < 0.0001) and an additive activity at 72 h with an HSA score of 8.61 (p < 0.0001). Molnupiravir and nirmatrelvir showed a synergistic activity both at 48 h and 72 h with an HSA score of 14.2 (p = 0.01) and 13.08 (p < 0.0001), respectively. Conclusion: Molnupiravir associated with one of the two protease-inhibitors nirmatrelvir and GC376 showed good additive-synergic activity in vitro.

Pre and Post-Monoclonal Infusion Neutralizing Activity in a Subgroup of Patients Treated in the Presence of two SARS-CoV-2 Dominant Variant of Concern (VOCs) and an Ongoing Vaccination. Overall Clinical Efficacy of Two Monoclonal Antibodies Association in Umbria.

Background and Objective: In patients with mild-to-moderate COVID-19 and at high risk of progression, casirivimab/imdevimab and bamlanivimab/etesivimab were utilized in Umbria from late April to November 2021. This period was characterized by an initial prevalence of alpha (B1.1.1.7) and its progressive substitution with the delta variant (B1.617.2). Many delta infections occurred in patients already recently vaccinated.Our study aimed to observe the clinical outcome of patients treated with mAbs associations in a subgroup in which viral isolation was obtained, the pre and post-infusion neutralizing antibody activity against their viral isolate. Methods: In this retrospective observational study, the clinical outcome before and 30 days after infusion, the baseline neutralizing activity of sera against their viral isolate, and the titers of neutralizing antibodies (NAbTs) one-hour post-infusion relative to the type of mAbs associations were evaluated. Results: Better efficacy of the mAbs combinations relative to monotherapy regarding global hospitalization (p = 0.021) and 30 days symptoms (p<0.001) were seen. Infections after vaccination mostly occurred in the absence of neutralizing antibody titers (NAbT). SARS-CoV-2 delta variants were isolated within 2-4 months from vaccinations without NAbTs, or in the presence of high specific neutralizing activity after 5-6 months. NAbTs were higher after casirivimab/imdevimab infusion (p=0.001). Conclusions: Alpha infections occurred prevalently in unvaccinated patients or after 5-6 months, while delta infections prevailed in vaccinated ones. A poor neutralizing activity in most of these patients was seen. A higher NAbT after infusion of casirivimab/imdevimab was observed.

Carriers of ADAMTS13 Rare Variants Are at High Risk of Life-Threatening COVID-19.

Thrombosis of small and large vessels is reported as a key player in COVID-19 severity. However, host genetic determinants of this susceptibility are still unclear. Congenital Thrombotic Thrombocytopenic Purpura is a severe autosomal recessive disorder characterized by uncleaved ultra-large vWF and thrombotic microangiopathy, frequently triggered by infections. Carriers are reported to be asymptomatic. Exome analysis of about 3000 SARS-CoV-2 infected subjects of different severities, belonging to the GEN-COVID cohort, revealed the specific role of vWF cleaving enzyme ADAMTS13 (A disintegrin-like and metalloprotease with thrombospondin type 1 motif, 13). We report here that ultra-rare variants in a heterozygous state lead to a rare form of COVID-19 characterized by hyper-inflammation signs, which segregates in families as an autosomal dominant disorder conditioned by SARS-CoV-2 infection, sex, and age. This has clinical relevance due to the availability of drugs such as Caplacizumab, which inhibits vWF-platelet interaction, and Crizanlizumab, which, by inhibiting P-selectin binding to its ligands, prevents leukocyte recruitment and platelet aggregation at the site of vascular damage.

Epidemiology, aetiology and treatment of skin and soft tissue infections: final report of a prospective multicentre national registry.

Skin and soft tissue infections (SSTIs) represent a heterogenous group of pathological conditions involving the skin or the underlying subcutaneous tissues, fascia and muscle, characterised by a considerable variety of clinical presentations, severity and possible aetiological pathogens. Although previous analyses on restricted types of SSTIs and population have already been published, we conducted a large nationwide surveillance program on behalf of the Italian Society of Infectious and Tropical Diseases to assess the clinical and microbiological characteristics of the whole SSTI spectrum, from mild to severe life-threatening infections, in both inpatients and outpatients and their management. Twenty-nine Infectious Diseases (ID) Centres throughout Italy collected prospectively data concerning both the clinical and microbiological diagnosis of patients affected by SSTIs via an electronic case report form. We included in our database all cases managed by ID specialists participating to the study, independently from their severity or the setting of consultation. Here, we integrated previous preliminary results analysing and reporting data referring to a 3-year period (October 2016-October 2019). During this period, the study population included 478 adult patients with diagnosis of SSTI. The type of infection diagnosed, the aetiological agent involved and some notes on antimicrobial susceptibilities were collected and reported herein. We also analysed the most common co-morbidities, the type and duration of therapy executed, before and after ID intervention and the length of stay. The results of our study provide information to better understand the national epidemiologic data and the current clinical management of SSTIs in Italy.

The association between neutrophil to lymphocyte ratio and endothelial dysfunction in people living with HIV on stable antiretroviral therapy.

BACKGROUND: Residual inflammation is thought to promote endothelial dysfunction and cardiovascular disease risk among people living with HIV (PLWH) receiving antiretroviral therapy (ART). Whether the neutrophil-to-lymphocyte ratio (NLR), a putative marker of systemic inflammation, may be associated with endothelial dysfunction has not been investigated in PLWH on stable ART. RESEARCH DESIGN AND METHODS: In this cross-sectional study, 210 PLWH (mean age 49 years, 79% males, 88/7/5% Caucasians/Africans/Hispanics) on long-term ART (median ART duration 8 years) were enrolled among those who were afferent to an Infectious Diseases outpatient clinic. The association between NLR and brachial flow-mediated dilation (bFMD) was analysed. RESULTS: A curvilinear association was observed between logarithmic-NLR and logarithmic-bFMD (R square = 0.034, p = 0.027), with logarithmic-bFMD decreasing significantly with increasing logarithmic-NLR only in PLWH with high NLR (≥1.47, median NLR) (r = -0.369, p < 0.001). However, NLR had a poor accuracy in the prediction of low bFMD (≤4.55, median bFMD) in PLWH with high NLR (55% sensitivity, 80% specificity, Youden index 0.35 for NLR 2.20). CONCLUSIONS: Although there is an inverse association between NLR and bFMD among long-term ART-treated PLWH with high NLR, NLR has a low discriminatory ability toward endothelial dysfunction in this category of patients.

Early Treatment with Bamlanivimab Alone does not Prevent COVID-19 Hospitalization and Its Post-Acute Sequelae. A Real Experience in Umbria, Italy.

BACKGROUND AND OBJECTIVE: The use of monoclonal antibodies to the SARS-Cov-2 spike protein for early treatment of COVID-19 disease is being evaluated, with only phase 2 studies available to date. The emergency authorization of bamlanivimab monotherapy was obtained in November 2020 by the FDA and in March 2021 by Italian agency AIFA. Its use was then revoked in April 2021 by both. This study reports the results of bamlanivimab utilization in monotherapy in Umbria (Italian region) to verify whether, in a population with multiple risk factors, comparable results to the phase 2 BLAZE1 trial had been obtained. METHODS: Between March and April 2021, a retrospective observational study was performed on patients treated with bamlanivimab. Demographic and clinical characteristics before and after infusion were evaluated. Moreover, a telephone interview was conducted about 30 days after the infusion to evaluate the overall course. RESULTS: All patients had an early infection (mean 4±1.73 days), almost all by alpha variant (97%). No adverse events to treatment were observed. Altogether within 30 days, the hospitalization rate was 20%, 15% for COVID-19 related pathologies, versus 4% at 11 days in the BLAZE1 phase 2 study. In addition, worsening of some symptoms observed at baseline such as asthenia (77 vs. 51.3%), shortness of breath (38 vs. 23%) was registered, as well as the onset of non-restorative sleep (41%). CONCLUSION: The clinical outcome after bamlanivimab monotherapy was far below the expectation despite the patients had been infected by a theoretically sensitive viral variant.

Low Brachial Artery Flow-Mediated Dilation Predicts Worse Prognosis in Hospitalized Patients with COVID-19.

BACKGROUND: Endothelial injury can be induced by coronavirus disease 2019 (COVID-19) and seems to exert a crucial pathogenic role in its most severe clinical manifestations. We aimed to investigate the association between brachial artery flow-mediated dilation (bFMD), a potential clinical and non-invasive measure of endothelial function, and in-hospital prognosis of COVID-19 patients. METHODS: Brachial artery flow-mediated dilation was assessed in hospitalized COVID-19 patients within 48 h of hospital admission. The association between bFMD and either intensive care unit (ICU) admission or in-hospital death was explored using univariable and multivariable analyses. RESULTS: Four hundred and eight patients were enrolled. Significantly lower bFMD values emerged in COVID-19 patients with either radiographic signs of pneumonia, respiratory distress, or the need for non-invasive ventilation compared with patients without these signs (p < 0.001, p = 0.001, and p < 0.001, respectively). Forty-two (10%) patients were admitted to the ICU, 76 (19%) patients died, and 118 (29%) patients met the composite endpoint of ICU admission/in-hospital death. At unadjusted Cox regression analysis showed that low bFMD (<4.4%, the median value) was associated with a higher risk for the composite endpoint of ICU admission/in-hospital death compared with high bFMD (≥4.4%, the median value) (HR 1.675, 95% CI 1.155-2.428, p = 0.007). Multi-adjusted Cox regression analyses showed that low bFMD was independently associated with a 1.519- to 1.658-fold increased risk for the composite endpoint of ICU admission/in-hospital death. CONCLUSIONS: Low bFMD predicts an unfavorable in-hospital prognosis in COVID-19 patients. The measurement of bFMD may be clinically useful in the prognostic stratification of COVID-19 patients upon hospital admission.

Role of Nucleocapsid Protein Antigen Detection for Safe End of Isolation of SARS-CoV-2 Infected Patients with Long Persistence of Viral RNA in Respiratory Samples.

BACKGROUND: In SARS-CoV-2 infection, viral RNA may persist in respiratory samples for several weeks after the resolution of symptoms. Criteria to assess the end of infectivity are not unequivocally defined. In some countries, time from diagnosis is the unique criterion used, in addition to symptom cessation. This study evaluates the role of the Lumipulse® Antigen Assay (LAA) for the safe end of isolation of patients ≥21 days after the diagnosis of infection. METHODS: A total of 671 nasopharyngeal swabs from patients diagnosed with infection at least 21 days before were assessed by RT-PCR and LAA, and the role of LAA in predicting the absence of infectivity was evaluated by virus cell culture. RESULTS: Viable virus was present in 10/138 cultured samples. Eight out of ten infective patients suffered from a concomitant disease, predisposing them to long-term shedding of infective virus. In particular, infectious virus was isolated from 10/20 RT-PCR+/LAA+ cultured samples, whereas no viable virus was found in all 118 RT-PCR+/LAA- cultured swabs. LLA and RT-PCR agreed in 484/671 (72.1%) samples, with 100% and 26.7% concordance in RT-PCR negative and positive samples, respectively. CONCLUSIONS: Viable virus can be found ≥21 days after diagnosis in immunocompromised or severely ill patients. LAA better than RT-PCR predicts non-infectivity of patients and can be safely used to end isolation in cases with long persistence of viral RNA in the respiratory tract.