BACKGROUND Artemisinin resistance in Plasmodium falciparum has emerged in Southeast Asia and now poses a threat to the control and elimination of malaria. Mapping the geographic extent of resistance is essential for planning containment and elimination strategies. METHODS Between May 2011 and April 2013, we enrolled 1241 adults and children with acute, uncomplicated falciparum malaria in an open-label trial at 15 sites in 10 countries (7 in Asia and 3 in Africa). Patients received artesunate, administered orally at a daily dose of either 2 mg per kilogram of body weight per day or 4 mg per kilogram, for 3 days, followed by a standard 3-day course of artemisinin-based combination therapy. Parasite counts in peripheral-blood samples were measured every 6 hours, and the parasite clearance half-lives were determined. RESULTS The median parasite clearance half-lives ranged from 1.9 hours in the Democratic Republic of Congo to 7.0 hours at the Thailand–Cambodia border. Slowly clearing in fections (parasite clearance half-life >5 hours), strongly associated with single point mutations in the “propeller” region of the P. falciparum kelch protein gene on chromosome 13 (kelch13), were detected throughout mainland Southeast Asia from southern Vietnam to central Myanmar. The incidence of pretreatment and post-treatment gametocytemia was higher among patients with slow parasite clearance, suggesting greater potential for transmission. In western Cambodia, where artemisinin-based combination therapies are failing, the 6-day course of antimalarial therapy was associated with a cure rate of 97.7% (95% confidence interval, 90.9 to 99.4) at 42 days. CONCLUSIONS Artemisinin resistance to P. falciparum, which is now prevalent across mainland Southeast Asia, is associated with mutations in kelch13. Prolonged courses of artemisinin-based combination therapies are currently efficacious in areas where standard 3-day treatments are failing. (Funded by the U.K. Department of International Development and others; ClinicalTrials.gov number, NCT01350856.)

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The nucleocapsid (N) protein is an important antigen for coronavirus, which participate in RNA package and virus particle release. In this study, we expressed the N protein of SARS-CoV-2 and characterized its biochemical properties. Static light scattering, size exclusive chromatography, and small-angle X-ray scattering (SAXS) showed that the purified N protein is largely a dimer in solution. CD spectra showed that it has a high percentage of disordered region at room temperature while it was best structured at 55 C, suggesting its structural dynamics. Fluorescence polarization assay showed it has non-specific nucleic acid binding capability, which raised a concern in using it as a diagnostic marker. Immunoblot assays confirmed the presence of IgA, IgM and IgG antibodies against N antigen in COVID-19 infection patients' sera, proving the importance of this antigen in host immunity and diagnostics.

Several studies show that the immunosuppressive drugs targeting the interleukin-6 (IL-6) receptor, including tocilizumab, ameliorate lethal inflammatory responses in COVID-19 patients infected with SARS-CoV-2. Here, by employing single-cell analysis of the immune cell composition of two severe-stage COVID-19 patients prior to and following tocilizumabinduced remission, we identify a monocyte subpopulation that contributes to the inflammatory cytokine storms. Furthermore, although tocilizumab treatment attenuates the inflammation, immune cells, including plasma B cells and CD8 + T cells, still exhibit robust humoral and cellular antiviral immune responses. Thus, in addition to providing a highdimensional dataset on the immune cell distribution at multiple stages of the COVID-19, our work also provides insights into the therapeutic effects of tocilizumab, and identifies potential target cell populations for treating COVID-19-related cytokine storms.

SummaryBackgroundMost malaria deaths occur in rural areas. Rapid progression from illness to death can be interrupted by prompt, effective medication. Antimalarial treatment cannot rescue terminally ill patients but could be effective if given earlier. If patients who cannot be treated orally are several hours from facilities for injections, rectal artesunate can be given before referral and acts rapidly on parasites. We investigated whether this intervention reduced mortality and permanent disability.MethodsIn Bangladesh, Ghana, and Tanzania, patients with suspected severe malaria who could not be treated orally were allocated randomly to a single artesunate (n=8954) or placebo (n=8872) suppository by taking the next numbered box, then referred to clinics at which injections could be given. Those with antimalarial injections or negative blood smears before randomisation were excluded, leaving 12 068 patients (6072 artesunate, 5996 placebo) for analysis. Primary endpoints were mortality, assessed 7–30 days later, and permanent disability, reassessed periodically. All investigators were masked to group assignment. Analysis was by intention to treat. This study is registered in all three countries, numbers ISRCTN83979018, 46343627, and 76987662.ResultsMortality was 154 of 6072 artesunate versus 177 of 5996 placebo (2·5% vs 3·0%, p=0·1). Two versus 13 (0·03% vs 0·22%, p=0·0020) were permanently disabled; total dead or disabled: 156 versus 190 (2·6% vs 3·2%, p=0·0484). There was no reduction in early mortality (56 vs 51 deaths within 6 h; median 2 h). In patients reaching clinic within 6 h (median 3 h), pre-referral artesunate had no significant effect on death after 6 h or permanent disability (71/4450 [1·6%] vs 82/4426 [1·9%], risk ratio 0·86 [95% CI 0·63–1·18], p=0·35). In patients still not in clinic after more than 6 h, however, half were still not there after more than 15 h, and pre-referral rectal artesunate significantly reduced death or permanent disability (29/1566 [1·9%] vs 57/1519 [3·8%], risk ratio 0·49 [95% CI 0·32–0·77], p=0·0013).InterpretationIf patients with severe malaria cannot be treated orally and access to injections will take several hours, a single inexpensive artesunate suppository at the time of referral substantially reduces the risk of death or permanent disability.FundingUNICEF/UNDP/World Bank Special Programme for Research and Training in Tropical Diseases (WHO/TDR); WHO Global Malaria Programme (WHO/GMP); Sall Family Foundation; the European Union (QLRT-2000-01430); the UK Medical Research Council; USAID; Irish Aid; the Karolinska Institute; and the University of Oxford Clinical Trial Service Unit (CTSU).

Background: Compared to adults, there are relatively few studies on COVID-19 infection in children, and even less focusing on the unique features of COVID-19 in children in terms of laboratory findings, locations of computerized tomography (CT) lesions, and the role of CT in evaluating clinical recovery. The objective of this study is to report the results from patients at Wuhan Children's Hospital, located within the initial center of the outbreak.Methods: Clinical, imaging, and laboratory data of 76 children were collected retrospectively and analyzed with the Fisher exact test and Cox regression statistical methods.Results: Among 50 children with a positive COVID-19 real-time reverse-transcriptase polymerase chain reaction (PCR), five had negative PCR results initially but showed positive results in subsequent tests. Eight (16%) patients had lymphopenia, seven (14%) with thrombocytopenia, four (8%) with lymphocytosis, two (4%) with thrombocytosis, ten (20%) with elevated C-reactive protein, four (8%) with hemoglobin above, and six (12%) with below standard reference values. Seven (14%) of the 50 had no radiologic evidence of disease on chest CT. For the 43 patients who had abnormal CT findings, in addition to previously reported patterns of ground-glass opacity (67%), local patchy shadowing (37%), local bilateral patchy shadowing (21%), and lesion location of lower lobes (65%), other CT features include that an overwhelming number of pediatric patients had lesions in the subpleural area (95%) and 22 of the 28 lower lobe lesions were in the posterior segment (78%). Lesions in most of the 15 patients (67%) who received chest CT at discharge were not completely absorbed, and 26% of these pediatric patients had CT lesions that were either unchanged or worse.(Continued on next page)

Highlights 42  Developed a highly quantitative and sensitive serologic immunoassay for SARS-CoV-2-specific 43 IgA, IgM and IgG in COVID-19 patients. 44  Showed the inclusion of IgA to the conventional IgM + IgG in a serological test improves the 45 performance. 46  Revealed the kinetics of three antibody isotypes in COVID-19 patients. 47  Observed that serum IgA level positively correlated with COVID-19 disease severity. 48 49 Abstract 50 Background 51 The current pandemic of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has52 caused a great loss in lives and economy. Detecting viral RNAs on nasopharyngeal and throat swabs is 53 the standard approach for SARS-CoV-2 diagnosis with variable success. Currently, there are only a few 54 studies describing the serological diagnostic methods that involve the detection of SARS-CoV-2-specific 55 IgM and IgG. Here, we aimed to develop a more quantitative and sensitive serological test for COVID-56 19 diagnosis, monitoring and clinical investigation, based on the detection of antigen-specific IgA as 57 well as IgM and IgG in blood in response to SARS-CoV-2 infection. 58 59 Methods 60 In this investigation, we report the development of a set of validated diagnostic kits for detecting serum 61 IgA, IgM, and IgG specific to SARS-CoV-2 nucleocapsid protein (NP) and receptor-binding domain 62 (RBD) of the spike protein by chemi-luminescence immuno-analysis. The kits were tested with a cohort 63 of 216 sera from 87 laboratory-confirmed COVID-19 patients, and 483 sera from SARS-CoV-2 negative 64 or healthy individuals as negative controls. A standard receiver operating characteristic (ROC) analysis 65 was conducted to evaluate the diagnostic accuracy. Using the kits, serum levels of IgA, IgM, and IgG 66 were analyzed, in response to SARS-CoV-2 infection and COVID-19 pathogenesis. 68 Findings 69The diagnostic kits based on the RBD antigen outperformed those based on the NP. RBD-specific IgA, 70IgM, and IgG detection kits showed sensitivities of 98· 6%, 96· 8%, and 96· 8%, and specificities of 98· 1%, 7192· 3%, and 99· 8%, respectively. In addition, using purified RBD-specific immunoglobulins from a 72 serum pool of COVID-19 patients as standards, the serum concentrations of RBD-specific IgA, IgM, and 73 IgG proteins were determined. The concentrations varied widely among different patients. Median 74 concentration of IgA and IgM reached peaks at 16-20 days after illness onset at 8· 84 μg/mL and 7· 25 75 μg/mL, respectively, while median concentration of IgG peaked during 21-25 days after illness onset at 76 16· 47 μg/mL. Furthermore, the serum IgA level positively correlates with COVID-19 severity. 77 78 Interpretation 79

Background: 2019 novel coronavirus disease (COVID-19) has posed significant threats to public health. To identify and treat the severe and critical patients with COVID-19 is the key clinical problem to be solved. The present study aimed to evaluate the clinical characteristics of severe and non-severe patients with COVID-19. Methods:We searched independently studies and retrieved the data that involved the clinical characteristics of severe and non-severe patients with COVID-19 through database searching. Two authors independently retrieved the data from the individual studies, assessed the study quality with Newcastle-Ottawa Scale and analyzed publication bias by Begg's test. We calculated the odds ratio (OR) of groups using fixed or randomeffect models.Results: Five studies with 5,328 patients confirmed with COVID-19 met the inclusion criteria.Severe patents were older and more common in dyspnea, vomiting or diarrhea, creatinine >104 μmol/L, procalcitonin ≥0.05 ng/mL, lymphocyte count <1.5×10 9 /L and bilateral involvement of chest CT. Severe patents had higher risk on complications including acute cardiac injury (OR 13.48; 95% CI, 3.60 to 50.47,