Advances And Challenges In Using Nirmatrelvir And Its Derivatives Against Sars-Cov-2 Infection.

On 22 December 2021, the United States Food and Drug Administration (FDA) approved the first Mpro inhibitor, i.e., oral antiviral nirmatrelvir (PF-07321332)/ritonavir (Paxlovid), for the treatment of early severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Nirmatrelvir inhibits SARS-CoV-2 infection, but high doses or long-term treatment may cause embryonic developmental toxicity and changes in host gene expression. The chiral structure of nirmatrelvir plays a key role in its antiviral activity. Ritonavir boosts the efficacy of nirmatrelvir by inactivating cytochrome P450 3A4 (CYP3A4) expression and occupying the plasma protein binding sites. Multidrug resistance protein 1 (MDR1) inhibitors may increase the efficacy of nirmatrelvir. However, paxlovid has many contraindications. Some patients treated with paxlovid experience a second round of coronavirus disease 2019 (COVID-19) symptoms soon after recovery. Interestingly, the antiviral activity of nirmatrelvir metabolites, such as compounds 12-18, is similar to or higher than that of nirmatrelvir. Herein, we review the advances and challenges in using nirmatrelvir and its derivatives with the aim of providing knowledge to drug developers and physicians in the fight against COVID-19.

Evidence of SARS-CoV-2-Specific T-Cell-Mediated Myocarditis in a MIS-A Case.

A 26-year-old otherwise healthy man died of fulminant myocarditis. Nasopharyngeal specimens collected premortem tested negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Histopathological evaluation of the heart showed myocardial necrosis surrounded by cytotoxic T-cells and tissue-repair macrophages. Myocardial T-cell receptor (TCR) sequencing revealed hyper-dominant clones with highly similar sequences to TCRs that are specific for SARS-CoV-2 epitopes. SARS-CoV-2 RNA was detected in the gut, supporting a diagnosis of multisystem inflammatory syndrome in adults (MIS-A). Molecular targets of MIS-associated inflammation are not known. Our data indicate that SARS-CoV-2 antigens selected high-frequency T-cell clones that mediated fatal myocarditis.

Digital CRISPR-based method for the rapid detection and absolute quantification of nucleic acids.

Rapid diagnostics of adventitious agents in biopharmaceutical/cell manufacturing release testing and the fight against viral infection have become critical. Quantitative real-time PCR and CRISPR-based methods rapidly detect DNA/RNA in 1 h but suffer from inter-site variability. Absolute quantification of DNA/RNA by methods such as digital PCR reduce this variability but are currently too slow for wider application. Here, we report a RApid DIgital Crispr Approach (RADICA) for absolute quantification of nucleic acids in 40-60 min. Using SARS-CoV-2 as a proof-of-concept target, RADICA allows for absolute quantification with a linear dynamic range of 0.6-2027 copies/µL (R2 value > 0.99), high accuracy and low variability, no cross-reactivity to similar targets, and high tolerance to human background DNA. RADICA's versatility is validated against other targets such as Epstein-Barr virus (EBV) from human B cells and patients' serum. RADICA can accurately detect and absolutely quantify EBV DNA with similar dynamic range of 0.5-2100 copies/µL (R2 value > 0.98) in 1 h without thermal cycling, providing a 4-fold faster alternative to digital PCR-based detection. RADICA therefore enables rapid and sensitive absolute quantification of nucleic acids which can be widely applied across clinical, research, and biomanufacturing areas.

Clinical characteristics of emergency surgery patients infected with coronavirus disease 2019 (COVID-19) pneumonia in Wuhan, China.

BACKGROUND: We aimed to investigate clinical symptoms and epidemiologic features of emergency surgery patients infected with the 2019 novel coronavirus disease (COVID-19). More than 5 million people worldwide have been diagnosed with COVID-19 since December 2019 to the time of this publication. Thousands of emergency operations have been carried out since December 2019. To date, however, no literature has focused on the clinical symptoms of emergency surgery patients with COVID-19 pneumonia. METHODS: We conducted a retrospective cohort study of 164 emergency surgery patients with or without COVID-19 pneumonia in Zhongnan Hospital of Wuhan University in Wuhan, China, from January 1, 2020, to January 20, 2020. For this report, the final date of follow-up was February 5, 2020. The associated clinical, laboratory, epidemiologic, demographic, radiologic, and outcome data were collected and analyzed. RESULTS: Of the 164 emergency surgery patients, the median age was 41 years (interquartile range, 29-89), and 136 (82.9%) were women. The associated main clinical symptom included fever (93 [56.7%])，dry cough (56 [34.2%]), fatigue (86 [52.4%]), nausea (78 [47.6%]), and dizziness (77 [47%]). Of 54 emergency surgery patients infected with COVID-19, the median age was 46 years (interquartile range: 25-89), and 45 (83.3%) were women. The pathologic clinical symptoms investigated included fever (54 [100%]), fatigue (48 [88.9%]), nausea (52 [96.3%]), dizziness (46 [85.2%]), and dry cough (44 [81.5%]). The lymphopenia (0.37 × 109/L [interquartile range: 0.23-0.65]) and increased C-reactive protein (24.7 × 109/L [interquartile range: 13.57-38]) were observed. The preoperative fever and postoperative fever in emergency surgery patients with or without COVID-19 pneumonia were analyzed in this study. Of 54 emergency surgery patients with COVID-19, 15 (27.8%) showed preoperative fever, 54 (100%) had postoperative fever. Of 110 emergency surgery patients without COVID-19, 5 (4.5%) had preoperative fever, 31 (28.2%) patients had postoperative fever. In emergency surgery patients with COVID-19, the fever lasted more than 7 days, markedly exceeded the length of time non-COVID-19 patients experienced fever (approximately 3 days). Furthermore, 43 health care workers were exposed to emergency surgery patients with COVID-19 pneumonia and were infected with COVID-19 pneumonia. CONCLUSION: In our study, the clinical symptoms of emergency surgery patients infected with COVID-19 displayed marked differences from those reporting common COVID-19 pneumonia. In addition, the health care workers were suspected to have been exposed to a great risk when caring for emergency surgery patients with COVID-19 pneumonia. Management guidelines of emergency surgery patients are described in in this report.