Non-randomized evaluation of hospitalization after a prescription for nirmatrelvir/ritonavir versus molnupiravir in high-risk COVID-19 outpatients.

OBJECTIVES: To assess and compare subsequent hospital admissions within 30 days for patients after receiving a prescription for either oral nirmatrelvir/ritonavir or oral molnupiravir. METHODS: We conducted a retrospective review of 3207 high-risk, non-hospitalized adult COVID-19 patients who received a prescription for molnupiravir (n = 209) or nirmatrelvir/ritonavir (n = 2998) at an academic medical centre in New York City from April to December 2022. Variables including age, vaccination status, high-risk conditions and demographic factors were pulled from the electronic medical record. We used multivariable logistic regression to adjust for potential confounding variables. RESULTS: All-cause 30 day hospitalization was not significantly different between patients who received nirmatrelvir/ritonavir compared with molnupiravir (1.4% versus 1.9%, P value = 0.55). The association between COVID-related hospitalization and medication was also not significant (0.7%versus 0.5%, P value = 0.99). Patients who received molnupiravir were more likely to have more underlying high-risk conditions. After adjusting for potential confounders, the odds of all-cause hospitalizations were not significantly different between patients who received nirmatrelvir/ritonavir compared with molnupiravir (OR = 1.16, 95% CI: 0.4-3.3, P value = 0.79). CONCLUSIONS: These data provide additional evidence to support molnupiravir as a suitable alternative when other COVID-19 antivirals cannot be given.

Expanding the scope and visibility of ambulatory stewardship programs with novel coronavirus disease 2019 (COVID-19) therapeutics

Antimicrobial stewardship programs (ASPs) can be expanded to the outpatient setting to serve as a first line of defense against coronavirus disease 19 (COVID-19) hospitalizations and to reduce the burden on emergency departments and acute-care hospitals. Given the numerous emergency use authorizations of monoclonal antibodies and oral antivirals, ASPs possess the expertise and leadership to direct ambulatory COVID-19 initiatives and transform it into a predominantly outpatient illness. In this review, we summarize the critical role and benefits of an ASP-championed ambulatory COVID-19 therapeutics program.

Expanding the scope and visibility of ambulatory stewardship programs with novel coronavirus disease 2019 (COVID-19) therapeutics.

Antimicrobial stewardship programs (ASPs) can be expanded to the outpatient setting to serve as a first line of defense against coronavirus disease 19 (COVID-19) hospitalizations and to reduce the burden on emergency departments and acute-care hospitals. Given the numerous emergency use authorizations of monoclonal antibodies and oral antivirals, ASPs possess the expertise and leadership to direct ambulatory COVID-19 initiatives and transform it into a predominantly outpatient illness. In this review, we summarize the critical role and benefits of an ASP-championed ambulatory COVID-19 therapeutics program.

Complement activation induces excessive T cell cytotoxicity in severe COVID-19

Severe COVID-19 is linked to both dysfunctional immune response and unrestrained immunopathology, and it remains unclear whether T cells contribute to disease pathology. Here, we combined single-cell transcriptomics and single-cell proteomics with mechanistic studies to assess pathogenic T cell functions and inducing signals. We identified highly activated CD16(+) T cells with increased cytotoxic functions in severe COVID-19. CD16 expression enabled immune-complex-mediated, T cell receptor-independent degranulation and cytotoxicity not found in other diseases. CD16(+) T cells from COVID-19 patients promoted microvascular endothelial cell injury and release of neutrophil and monocyte chemoattractants. CD16(+) T cell clones persisted beyond acute disease maintaining their cytotoxic phenotype. Increased generation of C3a in severe COVID-19 induced activated CD16(+) cytotoxic T cells. Proportions of activated CD16(+) T cells and plasma levels of complement proteins upstream of C3a were associated with fatal outcome of COVID-19, supporting a pathological role of exacerbated cytotoxicity and complement activation in COVID-19.

A Multicompartment Mathematical Model Based on Host Immunity for Dissecting COVID-19 Heterogeneity

Background: As of early August 2021, more than 190 million people have developed coronavirus disease (COVID-19), a pandemic that has killed approximately 4 million people. Caused by acute respiratory syndrome coronavirus 2 (SARS-CoV-2), COVID-19 exhibited a highly variable clinical course, ranging from a high proportion of asymptomatic and mild infections to severe and fatal disease. However, the immunological determinants underlying the heterogeneity of COVID-19 remain to be fully elucidated. Methods: To systemically analyze the immunopathogenesis of COVID-19, a multicompartment mathematical model based on both immunological principles and COVID-19-related work performed by the scientific community was built to illustrate the dynamics of host immunity after SARS-CoV-2 infection. We used ordinary differential equations (ODEs) to simulate the time-dependent functions of immunologic variations in the four compartments, which were draining lymph nodes, peripheral blood, lung and distant lymph nodes and spleen. Our model consisted of equations for 109 immunologic variations, which contained 223 parameters. K was used to characterize the adequacy of the SARS-CoV-2-specific naïve T/B cell pool;K I represented the hill coefficient of antigen-presenting cell (APC) differentiation. Further, we used method of pseudo landscape to visualize the effect of APC capacity and the SARS-CoV-2-specific naïve T/B cell pool on clinical outcomes. Results: Based on both immunologic knowledge and extensive COVID-19-related work performed by the scientific community, we constructed a knowledge-driven mathematical model that incorporated SARS-CoV-2 infection, bacterial infection, leukocyte chemotaxis, innate immunity and adaptive immunity. The model simulated and predicted the different trajectories of the viral load, bacterial load, immune cells, cytokines and infected epithelial cells in patients with different severities. A higher viral load and longer virus-shedding period were observed in patients with higher severity, along with an increase in SARS-CoV-2-infected lung epithelial cells. The trajectories of both peripheral blood IL-6 and lymphocytes predicted COVID-19 outcomes. Based on the distribution, trafficking and differentiation of immune cells after SARS-CoV-2 infection, we proposed that early-stage lymphopenia is related to lymphocyte chemotaxis. The delayed initiation of both innate and adaptive immunity resulted in elevated SARS-CoV-2 shedding and was a pivotal cause of COVID-19 severity. Spatiotemporally, viral shedding and postviral bacterial infection evoked stronger innate immunity. Viral shedding could be restrained by the rapid initiation of APC, antibody-secreting cell (ASC) and cytotoxic T cell (CTL). Moreover, our model predicted that the insufficient SARS-CoV-2-specific naïve T/B cell pools and inactive APC caused a series of chain reactions, including viral shedding, bacterial infection, sepsis and cytokine storms. Finally, pseudopotential analysis revealed that a high state characterized by severe bacterial infections and cytokine storms was a stable attractor for patients with insufficient SARS-CoV-2-specific naïve T/B cells and inactive APC (Figure 1). Conclusion: Overall, our analysis provided a comprehensive view of the dynamics of host immunity after SARS-CoV-2 infection and highlighted that the antigen-specific naïve T/B cell pool and APC ability may essentially determine COVID-19 heterogeneity from an immunological standpoint. [Formula presented] Disclosures: No relevant conflicts of interest to declare.

Editorial - Infectious-disease research during a pandemic: the importance of global unity.

The orthopaedic and trauma community have faced the threat of infection since the introduction of operative fracture fixation many decades ago. The parallel emergence and spread of antimicrobial resistance in clinically relevant pathogens has the potential to significantly complicate patient care. This editorial serves to provide a global context to the issue of antimicrobial resistance and how infectious disease research in general plays a crucial role both on a global scale as evidenced by the current pandemic, but also on a more personal scale for the daily management of orthopaedic trauma patients. The special issue on Orthopaedic Infection in the eCM journal provides a snapshot of the clinically relevant basic research that is being performed in this field.