Discrimination of False Negative Results in RT-PCR Detection of SARS-CoV-2 RNAs in Clinical Specimens by Using an Internal Reference

Reverse transcription-polymerase chain reaction(RT-PCR)is an essential method for specific diagnosis of SARS-CoV-2 infection.Unfortunately,false negative test results are often reported.In this study,we attempted to determine the principal causes leading to false negative results of RT-PCR detection of SARS-CoV-2 RNAs in respiratory tract specimens.Multiple sputum and throat swab specimens from 161 confirmed COVID-19 patients were tested with a commercialfluorescent RT-PCR kit targeting the ORF1 ab and N regions of SARS-CoV-2 genome.The RNA level of a cellular housekeeping gene ribonuclease P/MRP subunit p30(RPP30)in these specimens was also assessed by RT-PCR.Data for a total of 1052 samples were retrospectively re-analyzed and a strong association between positive results in SARS-CoV-2 RNA tests and high level of RPP30 RNA in respiratory tract specimens was revealed.By using the ROC-AUC analysis,we identified Ct cutoff values for RPP30 RT-PCR which predicted false negative results for SARS-CoV-2 RT-PCR with high sensitivity(95.03%–95.26%)and specificity(83.72%–98.55%)for respective combination of specimen type and ampli-fication reaction.Using these Ct cutoff values,false negative results could be reliably identified.Therefore,the presence of cellular materials,likely infected host cells,are essential for correct SARS-CoV-2 RNA detection by RT-PCR in patient specimens.RPP30 could serve as an indicator for cellular content,or a surrogate indicator for specimen quality.In addition,our results demonstrated that false negativity accounted for a vast majority of contradicting results in SARS-CoV-2 RNA test by RT-PCR.

Tocilizumab in patients with moderate or severe COVID-19: a randomized, controlled, open-label, multicenter trial

Tocilizumab has been reported to attenuate the“cytokine storm”in COVID-19 patients.We attempted to verify the effectiveness and safety of tocilizumab therapy in COVID-19 and identify patients most likely to benefit from this treatment.We conducted a randomized,controlled,open-label multicenter trial among COVID-19 patients.The patients were randomly assigned in a 1:1 ratio to receive either tocilizumab in addition to standard care or standard care alone.The cure rate,changes of oxygen saturation and interference,and inflammation biomarkers were observed.Thirty-three patients were randomized to the tocilizumab group,and 32 patients to the control group.The cure rate in the tocilizumab group was higher than that in the control group,but the difference was not statistically significant(94.12%vs.87.10%,rate difference 95%CI−7.19%–21.23%,P=0.4133).The improvement in hypoxia for the tocilizumab group was higher from day 4 onward and statistically significant from day 12(P=0.0359).In moderate disease patients with bilateral pulmonary lesions,the hypoxia ameliorated earlier after tocilizumab treatment,and less patients(1/12,8.33%)needed an increase of inhaled oxygen concentration compared with the controls(4/6,66.67%;rate difference 95%CI−99.17%to−17.50%,P=0.0217).No severe adverse events occurred.More mild temporary adverse events were recorded in tocilizumab recipients(20/34,58.82%)than the controls(4/31,12.90%).Tocilizumab can improve hypoxia without unacceptable side effect profile and significant influences on the time virus load becomes negative.For patients with bilateral pulmonary lesions and elevated IL-6 levels,tocilizumab could be recommended to improve outcome.

CORRECTION:Correction to:Discrimination of False Negative Results in RT-PCR Detection of SARS-CoV-2 RNAs in Clinical Specimens by Using an Internal Reference

In the original version of Fig.41 and 4J,the cutoff lines were accidently shifted during figure layout.Figures 41 and 4J are re-drawn and provided below.

Epidemiological characteristics and clinical manifestations of pediatric patients with COVID-19 in China: A multicenter retrospective study

Importance:The Coronavirus disease 2019(COVID-19)global pandemic poses a considerable challenge for pediatricians.Objective:This study aimed to identify the epidemiological characteristics and clinical features of pediatric patients with COVID-19 in China.Methods:This multicenter retrospective study included pediatric patients from 46 hospitals in China,covering 12 provinces and two municipalities.Epidemiological,demographic,clinical,laboratory,treatment,and outcome data were analyzed.Results:In total,211 pediatric patients with COVID-19 were included in this study.The median age was 7.0 years(range:22 days to 18 years).Approximately 16.3%of the patients exhibited asymptomatic infections,23.0%had upper respiratory tract infections,and 60.7%had pneumonia,including two with severe pneumonia and one with critical illness.Approximately 78.7%of the pediatric patients occurred in familial clusters.The most three common symptoms or signs at onset in children with COVID-19 were fever(54.5%),cough(49.3%),and pharyngeal congestion(20.8%).Only 17.6%of the patients presented with decreased lymphocyte count,whereas 13.6%had increased lymphocyte count.Among the patients with pneumonia who exhibited abnormal chest computed tomography findings,18.2%(23/127)of the patients had no other symptoms.Generally,the chest radiographs showed abnormalities that affected both lungs(49.6%);ground-glass opacity(47.2%)was the most common manifestation.The cure and improvement rates were 86.7%(183/211)and 13.3%(28/211),respectively.Only one patient with an underlying condition received invasive mechanical ventilation;none of the patients died.Interpretation:Similar to adults,children of all age groups are susceptible to COVID-19.Fortunately,most pediatric patients have mild symptoms or remain asymptomatic,despite the high incidence of pneumonia.Decreased proportions of white blood cells and lymphocytes are less frequent in children than in adults.