Passive Immunity for Coronavirus Disease 2019: A Commentary on Therapeutic Aspects Including Convalescent Plasma

Potential of Endogenous Oxytocin in Endocrine Treatment and Prevention of COVID-19

Coronavirus disease 2019 or COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a significant threat to the health of human beings. While wearing mask, maintaining social distance and performing self-quarantine can reduce virus spreading passively, vaccination actively enhances immune defense against COVID-19. However, mutations of SARS-CoV-2 and presence of asymptomatic carriers frustrate the effort of completely conquering COVID-19. A strategy that can reduce the susceptibility and thus prevent COVID-19 while blocking viral invasion and pathogenesis independent of viral antigen stability is highly desirable. In the pathogenesis of COVID-19, endocrine disorders have been implicated. Correspondingly, many hormones have been identified to possess therapeutic potential of treating COVID-19, such as estrogen, melatonin, corticosteroids, thyroid hormone and oxytocin. Among them, oxytocin has the potential of both treatment and prevention of COVID-19. This is based on oxytocin promotion of immune-metabolic homeostasis, suppression of inflammation and pre-existing comorbidities, acceleration of damage repair, and reduction of individuals' susceptibility to pathogen infection. Oxytocin may specifically inactivate SARS-COV-2 spike protein and block viral entry into cells via angiotensin-converting enzyme 2 by suppressing serine protease and increasing interferon levels and number of T-lymphocytes. In addition, oxytocin can promote parasympathetic outflow and the secretion of body fluids that could dilute and even inactivate SARS-CoV-2 on the surface of cornea, oral cavity and gastrointestinal tract. What we need to do now is clinical trials. Such trials should fully balance the advantages and disadvantages of oxytocin application, consider the time- and dose-dependency of oxytocin effects, optimize the dosage form and administration approach, combine oxytocin with inhibitors of SARS-CoV-2 replication, apply specific passive immunization, and timely utilize efficient vaccines. Meanwhile, blocking COVID-19 transmission chain and developing other efficient anti-SARS-CoV-2 drugs are also important. In addition, relative to the complex issues with drug applications over a long term, oxytocin can be mobilized through many physiological stimuli, and thus used as a general prevention measure. In this review, we explore the potential of oxytocin for treatment and prevention of COVID-19 and perhaps other similar pathogens.

Convalescent Plasma for the Prevention and Treatment of COVID-19: A Systematic Review and Quantitative Analysis

BACKGROUND

The COVID-19 pandemic, caused by a novel coronavirus termed SARS-CoV-2, has spread quickly worldwide. Convalescent plasma (CP) obtained from patients following recovery from COVID-19 infection and development of antibodies against the virus is an attractive option for either prophylactic or therapeutic treatment, since antibodies may have direct or indirect antiviral activities and immunotherapy has proven effective in principle and in many clinical reports.

OBJECTIVE

We seek to characterize the latest advances and evidence in the use of CP for COVID-19 through a systematic review and quantitative analysis, identify knowledge gaps in this setting, and offer recommendations and directives for future research.

METHODS

PubMed, Web of Science, and Embase were continuously searched for studies assessing the use of CP for COVID-19, including clinical studies, commentaries, reviews, guidelines or protocols, and in vitro testing of CP antibodies. The screening process and data extraction were performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Quality appraisal of all clinical studies was conducted using a universal tool independent of study designs. A meta-analysis of case-control and randomized controlled trials (RCTs) was conducted using a random-effects model.

RESULTS

Substantial literature has been published covering various aspects of CP therapy for COVID-19. Of the references included in this review, a total of 243 eligible studies including 64 clinical studies, 79 commentary articles, 46 reviews, 19 guidance and protocols, and 35 in vitro testing of CP antibodies matched the criteria. Positive results have been mostly observed so far when using CP for the treatment of COVID-19. There were remarkable heterogeneities in the CP therapy with respect to patient demographics, donor antibody titers, and time and dose of CP administration. The studies assessing the safety of CP treatment reported low incidence of adverse events. Most clinical studies, in particular case reports and case series, had poor quality. Only 1 RCT was of high quality. Randomized and nonrandomized data were found in 2 and 11 studies, respectively, and were included for meta-analysis, suggesting that CP could reduce mortality and increase viral clearance. Despite promising pilot studies, the benefits of CP treatment can only be clearly established through carefully designed RCTs.

CONCLUSIONS

There is developing support for CP therapy, particularly for patients who are critically ill or mechanically ventilated and resistant to antivirals and supportive care. These studies provide important lessons that should inform the planning of well-designed RCTs to generate more robust knowledge for the efficacy of CP in patients with COVID-19. Future research is necessary to fill the knowledge gap regarding prevention and treatment for patients with COVID-19 with CP while other therapeutics are being developed.

Convalescent plasma treatment is associated with lower mortality and better outcomes in high-risk COVID-19 patients - propensity-score matched case-control study

OBJECTIVE

This study aimed to investigate the efficacy and safety of convalescent plasma (CP) transfusion in a group of high-risk COVID-19 patients.

METHODS

This prospective study included 204 patients from a single tertiary-care hospital, hospitalized with COVID-19, of whom 102 were treated with CP administration and standard care (PG) and 102 others who received standard care only (CG). The CG was selected from 336 hospitalized patients using the propensity-score matching (PSM) technique using age, MEWS score, and comorbidities. The primary outcome was mortality rate; secondary outcomes were the requirement of a ventilator, length of ventilator need, length of intensive care unit (ICU) stay, and length of overall hospital confinement. Additionally, parameters predicting death in COVID-19 patients were identified.

RESULTS

Findings confirmed a significantly lower mortality rate in the PG versus the CG (13.7% vs. 34.3 %, p = 0.001) and a significant difference in the cumulative incidence of death between the two groups (p <  0.001). CP treatment was associated with lower risk of death (OR = 0.25 CI95 [0.06; 0.91], p =  0.041). There were no significant differences in ICU stay, ventilator time, and hospitalization time between the two groups.

CONCLUSIONS

A significantly lower mortality rate was observed in the group of patients treated with CP. Age, presence of cardiac insufficiency, active cancer, a ventilator requirement, and length of hospitalization significantly increased the risk of death in both groups. Our study shows that CP affords better outcomes when administrated in the earlier stage of high-risk COVID-19 disease.

Antibody-based immunotherapeutics and use of convalescent plasma to counter COVID-19: advances and prospects

INTRODUCTION

Coronavirus disease 2019 (COVID-19) has spread to several countries globally. Currently, there is no specific drug or vaccine available for managing COVID-19. Antibody-based immunotherapeutic strategies using convalescent plasma, monoclonal antibodies (mAbs), neutralizing antibodies (NAbs), and intravenous immunoglobulins have therapeutic potential.

AREAS COVERED

This review provides the current status of the development of various antibody-based immunotherapeutics such as convalescent plasma, mAbs, NAbs, and intravenous immunoglobulins against COVID-19. The review also highlights their advantages, disadvantages, and clinical utility for the treatment of COVID-19 patients.

EXPERT OPINION

In a pandemic situation such as COVID-19, the development of new drugs should focus on and expedite the strategies where safety and efficacy are proven. Antibody-based immunotherapeutic approaches such as convalescent plasma, intravenous immunoglobulins, and mAbs have a proven record of safety and efficacy and are in use for decades. Some of them are already being used to manage COVID-19 patients and found to be useful. However, the mAbs with virus neutralization potential is the need of the hour during this COVID-19 pandemic to be more specific and virus targeted. The research and investment need to be accelerated to bring them into clinical use for prophylactic and therapeutic purposes against COVID-19.