ABSTRACT
BackgroundThe durability and cross-neutralizability of protective antibodies against evolving SARS-CoV-2 variants are primary concerns in mitigating (re-)exposures. The role of antibody maturation, the process whereby selection of higher avidity antibodies augments host immunity, to determine SARS-CoV-2 neutralizability was investigated. MethodsSera collected from SARS-CoV-2 convalescent individuals at 2- or 10-months after recovery, and BNT162b2 vaccine recipients at 3 or 25 weeks post-vaccination, were analyzed. Anti-spike IgG avidity was measured on a urea-treated ELISA platform. Neutralizing ability of antibodies was assessed by surrogate virus neutralization. Fold change between variant and wild-type antigen neutralizability was calculated to infer breadth of neutralizability. ResultsCompared with early-convalescence, the avidity index of late-convalescent sera was significantly higher (median 37.7 (interquartile range 28.4-45.1) vs. 64.9 (57.5-71.5), p < 0.0001), indicative of progressive antibody maturation extending months beyond acute-phase illness. The urea-resistant, high-avidity fraction of IgG was best predictive of neutralizability (Spearmans r = 0.49 vs. 0.67 for wild-type; 0.18-0.52 vs. 0.48-0.83 for variants). Higher-avidity convalescent sera showed greater cross-neutralizability against SARS-CoV-2 variants (p < 0.001 for Alpha; p < 0.01 for Delta and Omicron). Vaccinees experienced delayed maturation kinetics, translating to limited breadth of neutralizability at week-25 post-vaccination which was only comparable to that of early-convalescence. ConclusionsAvidity maturation grants broader neutralizability that is resilient against emerging SARS-CoV-2 variants. With immunopotentiation through repeat vaccinations becoming a pivotal strategy to accomplish herd immunity, understanding the variable longitudinal evolutions of the two building blocks of hybrid immunity is crucial.
ABSTRACT
BackgroundIn vitro drug-screening studies have indicated that camostat mesilate (FOY-305) may prevent SARS-CoV-2 infection into human airway epithelial cells. This study was conducted to investigate whether camostat mesilate is an effective treatment for SARS-CoV-2 infection (COVID-19). MethodsThis was a phase 3, multicentre, double-blind, randomised, parallel-group, placebo-controlled study. Patients were enrolled if they were admitted to a hospital within 5 days of onset of COVID-19 symptoms or within 5 days of a positive test for asymptomatic patients. Severe cases (e.g., those requiring oxygenation/ventilation) were excluded. Patients were administered camostat mesilate (600 mg qid; four to eight times higher than the clinical doses in Japan) or placebo for up to 14 days. The primary efficacy endpoint was the time to the first two consecutive negative tests for SARS-CoV-2. FindingsOne-hundred and fifty-five patients were randomised to receive camostat mesilate (n=78) or placebo (n=77). The median time to the first test was 11 days in both groups, and conversion to negative status was observed in 60{middle dot}8% and 63{middle dot}5% of patients in the camostat mesilate and placebo groups, respectively. The primary (Bayesian) and secondary (frequentist) analyses found no significant differences in the primary endpoint between the two groups. No additional safety concerns beyond those already known for camostat mesilate were identified. InterpretationCamostat mesilate is no more effective, based on upper airway viral clearance, than placebo for treating patients with mild to moderate SARS-CoV-2 infection with or without symptoms. FundingOno Pharmaceutical Co., Ltd. RESEARCH IN CONTEXT PANELO_ST_ABSEvidence before this studyC_ST_ABSSARS-CoV-2 infection (COVID-19), as a significant global health threat, is characterised by broad symptoms and varying disease severity. At the time of planning this study, there were no specific treatments for COVID-19 beyond the use of antiviral drugs, steroids and, in severe cases, ventilation with oxygen. Pre-clinical screening studies revealed the spike (S) protein of SARS-CoV-2 bind to angiotensin converting enzyme II (ACE2) on the host cell membrane. The S protein is then cleaved by a type II transmembrane serine protease (TMPRSS2) as an essential enzyme for the viral entry into host cells. In vitro drug-screening studies have shown that drugs that block binding of the S protein to ACE2 can prevent viral entry into a cell line derived from human airway epithelium. The studies identified 4-(4-guanidinobenzoyloxy)phenylacetic acid, the active metabolite of a serine protease inhibitor (camostat mesilate, FOY-305), as a candidate inhibitor of SARS-CoV-2 entry into humans. A retrospective study of critically ill COVID-19 patients with organ failure revealed a decline in disease activity within 8 days of admission among patients treated with camostat mesilate. In consideration of the preclinical and early clinical evidence, it was hypothesised that camostat mesilate is an effective treatment for patients with COVID-19. Therefore, we planned and executed a phase 3, randomised, double-blind, placebo-controlled study to investigate the efficacy and safety of camostat mesilate for the treatment of patients with mild to moderate COVID-19 infection with or without symptoms. The primary endpoint was the time to the first two consecutive negative tests for SARS-CoV-2. No controlled clinical studies of camostat mesilate had been conducted at the time of planning this study. Added value of this studyThe results of this randomised controlled trial revealed that camostat mesilate, administered at a dose of 600 mg qid for up to 14 days, was no more effective than placebo, based on upper airway viral clearance in patients with mild to moderate SARS-CoV-2 infection with or without symptoms. Furthermore, there were no differences between the study groups in terms of other efficacy endpoints. This study used a dose that was four to eight times higher than the clinical doses of camostat mesilate used in Japan for the acute symptoms of chronic pancreatitis and postoperative reflux oesophagitis. The study identified no additional safety concerns beyond those already known for camostat mesilate. Implications of all available evidenceAfter starting this study, another randomised, placebo-controlled study reported the efficacy and safety of camostat mesilate for the treatment of patients with COVID-19, albeit at a lower dose of 200 mg three times daily. That study also found no difference between camostat mesilate and placebo for the primary endpoint (the time to discharge or a clinical improvement in clinical severity of at least two points on a seven-point ordinal scale). Along with this evidence, our study did not support the use of camostat mesilate as a treatment option for COVID-19. However, since the administration of camostat mesilate was started after the onset of symptoms and presumably the peak viral load, we cannot exclude the possibility that camostat mesilate may be effective if administration is started earlier in the course of infection, or perhaps as prophylactic use in close contacts.
ABSTRACT
BackgroundThe impact of novel coronavirus disease 2019 (COVID-19) on healthcare workers (HCWs) has been under-evaluated in Central America. We performed a seroepidemiological survey at a tertiary healthcare facility in El Salvador, where a large number of confirmed and far more suspected cases of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infected HCWs had been documented during the first wave of the pandemic. MethodsDuring January-February 2021, a total 973 HCWs were tested for SARS-CoV-2 antibodies. Participants completed a questionnaire asking of their demographic data. Occupational risk was assessed by statistically comparing the seropositivity rates among different occupational categories. ResultsOverall seroprevalence in HCWs reached 52.6% (512 of 973). Of the seropositive individuals, 61.7% (316 of 512) had experienced a documented COVID-19 diagnosis, while the remaining 38.3% (196 of 512) were unrecognized seroconversions. Differences in seropositivity rates existed between occupational categories; nurses demonstrated the highest at 63.8% (222 of 348, risk ratio 1.44, p < 0.0001), followed by auxiliary HCWs assigned to patient-related work (55.9%, 52 of 93), and medical doctors (46.7%, 50 of 107). Several non-patient-related professions showed above-average seroprevalence, suggesting substantial SARS-CoV-2 contacts outside the workplace: 60.0% (6 of 10) and 68.0% (17 of 25) for nutritionists and pharmacists, respectively. ConclusionsSARS-CoV-2 seroprevalence exceeded 50% among HCWs in El Salvador, with disparity among occupational categories with different workplace exposure risks. Importance of not only nosocomial infection prevention but also screening for transmissions having occurred outside the workplace were highlighted to efficiently control nosocomial spreads during a pandemic wave. Key pointsHealthcare workers in El Salvador were tested for SARS-CoV-2 antibodies. Seroprevalence reached 52.6%, with disparity among occupation; nurses ranked highest at 63.8% seropositivity. Alongside nosocomial transmissions, high seroprevalence associated with non-patient-related work suggested substantial SARS-CoV-2 contacts outside the workplace.
ABSTRACT
BACKGROUND: The canonical Wnt/β-catenin signaling pathway is a fundamental regulatory system involved in various biological events. ICG-001 selectively blocks the interaction of β-catenin with its transcriptional co-activator cyclic AMP response element-binding protein (CBP). Recent studies have provided convincing evidence of the inhibitory effects of ICG-001 on Wnt-driven disease models, such as organ fibrosis, cancer, acute lymphoblastic leukemia, and asthma. However, the effects of ICG-001 in atopic dermatitis (AD) have not been investigated. OBJECTIVE: To investigate whether β-catenin/CBP-dependent signaling was contributed in the pathogenesis of AD and ICG-001 could be a therapeutic agent for AD. METHODS: We examined the effects of ICG-001 in an AD-like murine model generated by repeated topical application of the hapten, oxazolone (Ox). ICG-001 or vehicle alone was injected intraperitoneally every day during the development of AD-like dermatitis arising from once-daily Ox treatment. RESULTS: Ox-induced AD-like dermatitis characterized by increases in transepidermal water loss, epidermal thickness, dermal thickness accompanied by increased myofibroblast and mast cell counts, and serum levels of thymic stromal lymphopoietin and thymus and activation-regulated chemokine, and decreases in stratum corneum hydration, were virtually normalized by the treatment with ICG-001. Elevated serum levels of periostin tended to be downregulated, without statistical significance. CONCLUSION: These results suggest that β-catenin/CBP-dependent signaling might be involved in the pathogenesis of AD and could be a therapeutic target.
