Evaluation of the diagnostic accuracy of COVID-19 antigen tests: A systematic review and meta-analysis.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to affect countries worldwide. To inhibit the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), testing of patients, contact tracing, and quarantine of their close contacts have been used as major nonpharmaceutical interventions. The advantages of antigen tests, such as low cost and rapid turnaround, may allow for the rapid identification of larger numbers of infectious persons. This meta-analysis aimed to evaluate the diagnostic accuracy of antigen tests for SARS-CoV-2. METHODS: We searched PubMed, Embase, Cochrane Library, and Biomed Central databases from inception to January 2, 2021. Studies evaluating the diagnostic accuracy of antigen testing for SARS-CoV-2 with reference standards were included. We included studies that provided sufficient data to construct a 2 × 2 table on a per-patient basis. Only articles in English were reviewed. Summary sensitivity and specificity for antigen tests were generated using a random-effects model. RESULTS: Fourteen studies with 8624 participants were included. The meta-analysis for antigen testing generated a pooled sensitivity of 79% (95% CI, 66%-88%; 14 studies, 8624 patients) and a pooled specificity of 100% (95% CI, 99%-100%; 14 studies, 8624 patients). The subgroup analysis of studies that reported specimen collection within 7 days after symptom onset showed a pooled sensitivity of 95% (95% CI, 78%-99%; four studies, 1342 patients) and pooled specificity of 100% (95% CI, 97%-100%; four studies, 1342 patients). Regarding the applicability, the patient selection, index tests, and reference standards of studies in our meta-analysis matched the review title. CONCLUSION: Antigen tests have moderate sensitivity and high specificity for the detection of SARS-CoV-2. Antigen tests might have a higher sensitivity in detecting SARS-CoV-2 within 7 days after symptom onset. Based on our findings, antigen testing might be an effective method for identifying contagious individuals to block SARS-CoV-2 transmission.

Clinical applications and consideration of interventions of electrotherapy for orthopedic and neurological rehabilitation.

Electrotherapy or electrical stimulation (ES) is a part of clinical intervention in the rehabilitation field. With rehabilitation intervention, electrotherapy may be provided as a treatment for pain relief, strengthening, muscle education, wound recovery, or functional training. Although these interventions may not be considered as the primary therapy for patients, the advantages of the ease of operation, lower costs, and lower risks render ES to be applied frequently in clinics. There have also been emerging ES tools for brain modulation in the past decade. ES interventions are not only considered analgesics but also as an important assistive therapy for motor improvement in orthopedic and neurological rehabilitation. In addition, during the coronavirus disease pandemic, lockdowns and self-quarantine policies have led to the discontinuation of orthopedic and neurological rehabilitation interventions. Therefore, the feasibility and effectiveness of home-based electrotherapy may provide opportunities for the prevention of deterioration or extension of the original therapy. The most common at-home applications in previous studies showed positive effects on pain relief, functional ES, muscle establishment, and motor training. Currently, there is a lack of certain products for at-home brain modulation; however, transcranial direct current stimulation has shown the potential of future home-based rehabilitation due to its relatively small and simple design. We have organized the features and applications of ES tools and expect the future potential of remote therapy during the viral pandemic.

Expression of Endogenous Angiotensin-Converting Enzyme 2 in Human Induced Pluripotent Stem Cell-Derived Retinal Organoids.

Angiotensin-converting enzyme 2 (ACE2) was identified as the main host cell receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its subsequent infection. In some coronavirus disease 2019 (COVID-19) patients, it has been reported that the nervous tissues and the eyes were also affected. However, evidence supporting that the retina is a target tissue for SARS-CoV-2 infection is still lacking. This present study aimed to investigate whether ACE2 expression plays a role in human retinal neurons during SARS-CoV-2 infection. Human induced pluripotent stem cell (hiPSC)-derived retinal organoids and monolayer cultures derived from dissociated retinal organoids were generated. To validate the potential entry of SARS-CoV-2 infection in the retina, we showed that hiPSC-derived retinal organoids and monolayer cultures endogenously express ACE2 and transmembrane serine protease 2 (TMPRSS2) on the mRNA level. Immunofluorescence staining confirmed the protein expression of ACE2 and TMPRSS2 in retinal organoids and monolayer cultures. Furthermore, using the SARS-CoV-2 pseudovirus spike protein with GFP expression system, we found that retinal organoids and monolayer cultures can potentially be infected by the SARS-CoV-2 pseudovirus. Collectively, our findings highlighted the potential of iPSC-derived retinal organoids as the models for ACE2 receptor-based SARS-CoV-2 infection.