Lab results of COVID-19 patients:Omicron vs delta variants

BACKGROUND The coronavirus disease 2019(COVID-19)virus has been a world-known pan-demic since February 2020.Multiple variances had been established;the most common variants in Israel were omicron and delta.AIM To analyze and compare laboratory values in the"omicron"and"delta"variants of the coronavirus by conducting follow-up examinations and laboratory audits on COVID-19 patients admitted to our institution.METHODS A retrospective study,two groups,50 patients in each group.Patients examined positive for COVID-19 were divided into groups according to the common variant at the given time.We reviewed demographic data and laboratory results such as complete blood count and full chemistry,including electrolytes and coagulation parameters.RESULTS The mean age was 52%,66.53±21.7 were female.No significance was found comparing laboratory results in the following disciplines:Blood count,hemo-globin,and lymphocytes(P=0.41,P=0.87,P=0.97).Omicron and delta variants have higher neutrophil counts,though they are not significantly different(P=0.38).Coagulation tests:Activated paritial thromoplastin test and international normalized ratio(P=0.72,P=0.68).We found no significance of abnormality for all electrolytes.CONCLUSION The study compares laboratory results of blood tests between two variants of the COVID-19 virus–omicron and delta.We found no significance between the variants.Our results show the need for further research with larger data as well as the need to compare all COVID-19 variants.

Difference of Clinical Characteristics in Patients with Omicron and Delta Variants of SARS-CoV-2 in Beijing,China

Background Delta and Omicron are two main variants that have been prevalent since 2021.However,the Omicron variant of severe acute respiratory syndrome coronavirus 2 shows a less severe clinical presentation and high transmissibility.Therefore,we carried out this retrospective study to evaluate Omicron severity compared with the Delta variant and further comprehend the differences in clinical characteristics in patients with the Omicron variant.Methods We extracted clinical data and compared clinical severity,symptoms,vaccination status,laboratory parameters,viral shedding time,and computed tomography(CT)imaging between the two groups of patients,which included 109 COVID-19 cases with the Delta variant and 183 cases with the Omicron variant,from January 19 to April 1,2022,in Beijing Ditan Hospital.In addition,the Beijing Center for Disease Prevention and Control conducted whole-genome sequencing.Results We obtained 94 strains of variants of concern/Delta and 110 strains of variants of concern/Omicron.For the 110 Omicron strains,three were assigned as BA.1.1,53 as BA.2,and 54 as BA.2.2.Among patients with the Delta variant,54%(59/109)were moderate,which was significantly higher than that of patients with the Omicron variant(7%(12/183),P<0.001).The number of patients with mild symptoms in the Omicron group was significantly higher than in the Delta group(80%vs.35%,P<0.001).Compared with the Omicron group,patients with underlying diseases or obesity,60 years or older,or unvaccinated in the Delta group had more severe disease,and there was a significant difference between the two groups.The viral shedding time in the Omicron group was shorter than in the Delta group((11.9±5.9)vs.(14.0±5.8)days,P=0.003).Among the 183 patients in the Omicron group,104(57%)had dry or sore throat symptoms,more than those in the Delta group(34%(37/109);P<0.001).In the Delta group,patients in the moderate group had more fever and cough symptoms than those in the mild group.The remission time of CT imaging in the Omicron group was shorter than in the Delta group((9.0±5.2)vs.(13.2±4.2)days,P=0.018).Conclusions Patients with Delta variants are more likely to have pneumonia,mainly with fever and cough symptoms,while patients with the Omicron variant are mostly mild,with more prominent dry or sore throat symptoms.In addition,patients with the Omicron variant have a short viral shedding time and rapid absorption of pneumonia.

COVID-19 Delta variants—Current status and implications as of August 2021

The SARS-CoV-2 Delta variant has evolved as the dominant strain of the current pandemic.Studies have shown that this variant has increased infectivity/viral load,and reduced neutralization by the host antibodies from convalescent patients/vaccinees.Clinically,Delta variant infection has been observed/documented in convalescent patients/vaccinees,although with less incidence of severe diseases,but can serve as reservoir to spread the infection to the unvaccinated.The current understanding(as of 18 August 2021)on the virologic aspect(including the amino acid substitutions),clinical implications,and public health implications will be discussed in this mini review,and recommendations to health authorities will be provided.

A Retrospective Analysis of Wastewater Confirms Dominant Circulation of SARS-CoV-2 Delta Variant in Nairobi, Kenya, between April 2021 and August 2021

Wastewater surveillance has been applied in various parts of the world to monitor the introduction and transmissions of SARS-CoV-2 variants in a population. The knowledge of SARS-CoV-2 variants circulating in a population is critical to COVID-19 management and timing of the application of public health countermeasures. Contrary to the routine clinical surveillance of SARS-CoV-2 where cases from asymptomatic patients are often underreported, wastewater surveillance offers an unbiased tool for monitoring the extent of SARS-CoV-2 transmissions in a community. The present study aimed to characterize SARS-CoV-2 variants that circulated in Nairobi County, Kenya, between April 2021 and August 2021 utilizing wastewater samples. Viral RNA was extracted from wastewater samples, followed by SARS-CoV-2 screening by real-time RT-qPCR before targeted sequencing of the Spike gene. Forty samples were analyzed, of which 50% (n = 20) tested positive for SARS-CoV-2 by real-time RT-qPCR. Of these, 45% (n = 9) were successfully amplified by RT-PCR and sequenced. The majority (78%, 7/9) of the viruses belonged to the Delta (B.1.617.2) lineage of SARS-CoV-2, while a minority (22%) belonged to the Alpha (B.1.1.7) and Alpha-Delta lineages. Phylogenetic analysis of the SARS-COV-2 delta lineage strains revealed scattered clustering of the Kenyan viruses among the global strains included in the analysis, suggesting different introductory routes into the country. On the whole, our results confirm previous clinical findings that SARS-CoV-2 variants belonging to the Alpha (B.1.1.7) and Delta (B.1.617.2) lineages circulated in Nairobi County, Kenya during the study period, with the latter predominating. This is the first study to describe the diversity of SARS-CoV-2 variants circulating in Kenya, through wastewater analysis.

Case series in Indonesia:B.1.617.2(delta)variant of SARS-CoV-2 infection after a second dose of vaccine

BACKGROUND The B.1.617.2(delta)variant of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)was first discovered in Maharashtra in late 2020 and has rapidly expanded across India and worldwide.It took only 2 mo for this variant to spread in Indonesia,making the country the new epicenter of the delta variant as of July 2021.Despite efforts made by accelerating massive rollouts of current vaccines to protect against infection,cases of fully-vaccinated people infected with the delta variant have been reported.AIM To describe the demographic statistics and clinical presentation of the delta variant infection after the second dose of vaccine in Indonesia.METHODS A retrospective,single-centre case series of the general consecutive population that worked or studied at Faculty of Medicine,Universitas Indonesia with confirmed Delta Variant Infection after a second dose of vaccine from 24 June and 25 June 2021.Cases were collected retrospectively based on a combination of author recall,reverse transcription-polymerase chain reaction(RT-PCR),and whole genome sequencing results from the Clinical Microbiology Laboratory,Faculty of Medicine,Universitas Indonesia.RESULTS Between 24 June and 25 June 2021,15 subjects were confirmed with the B.1.617.2(delta)variant infection after a second dose of the vaccine.Fourteen subjects were vaccinated with CoronaVac(Sinovac)and one subject with ChAdOx1 nCoV-19(Oxford-AstraZeneca).All of the subjects remained in home isolation,with fever being the most common symptom at the onset of illness(n=10,66.67%).The mean duration of symptoms was 7.73 d(±5.444).The mean time that elapsed from the first positive swab to a negative RT-PCR test for SARS-CoV-2 was 17.93 d(±6.3464).The median time that elapsed from the second dose of vaccine to the first positive swab was 87 d(interquartile range:86-128).CONCLUSION Although this case shows that after two doses of vaccine,subjects are still susceptible to the delta variant infection,currently available vaccines remain the most effective protection.They reduce clinical manifestations of COVID-19,decrease recovery time from the first positive swab to negative swab,and lower the probability of hospitalization and mortality rate compared to unvaccinated individuals.

COVID-19 Infection: The Virus and Its Origin, the Variants, the Immune Defense, the Multiorgan Autoimmune Reactions, and the Targeted Treatments

Background: SARS-CoV-2, the virus responsible for the current COVID-19 infection pandemic, has caused substantial damage and negative impacts in the world, including physical sickness, mental illness, death, society lock down, work interruption, and productivity reduction. From the onset in early 2020, the pandemic has not yet totally subsided as of July 2022. Although great efforts have been made to understand the nature of this pandemic by the medical and scientific communities, a comprehensive review of this pandemic has not been reported. Purpose: We aimed to perform a thorough review of the subject in order to come to a better understanding of the origin of the virus, its mutations and their corresponding health effects, its pathophysiology, and its responses to therapeutic intervention. A more comprehensive set of data on these subject matters, if available, would give healthcare providers a valuable tool in formulating the best methods to respond to the current disease and prevent the disease from spreading in the future. Method: An extensive literature search on the subjects of COVID-19 was conducted regarding the possible origin of the viral pathogen, its evolutionary changes and health impacts, the world’s responses to COVID-19 and outcomes of their responses, and healthcare professional’s actions to understand and manage the disease and the results of their actions. To gather these data, websites of PubMed and Google Scholar were utilized for the search with the following keywords: Pandemic, COVID-19, coronavirus, SARS, SARS-CoV, SARS-CoV-2, origin, pathogenesis, and treatment. Results: Our review revealed data that points to an interesting autoimmune phenomenon where most seriously sick patients affected by COVID-19 were documented by an IgA-dominant immune response to the pathogen, along with a neutrophil-directed infiltration to the vital organ in the lung aveola, resulting in critical lung injury, leading to respiratory failure, multi-organ failure, and death. Surprisingly, this IgA-mediated and neutrophil-directed disease pattern is nearly identical to a group of IgA-mediated autoimmune skin diseases, such as dermatitis herpetiformis, IgA bullous dermatosis, and IgA pemphigus, which respond well to treatment by dapsone, a sulfone class of antibiotic/anti-inflammatory drug. Moreover, the usefulness of dapsone was supported by a small clinical study. In addition, systemic corticosteroid, a trusted anti-inflammatory medication, has been used in this pandemic with variable degrees of success. Conclusion: The data collected from our review of the subject, together with our prior search knowledge, compel us to conclude that the underlying pathophysiology that causes serious respiratory distress and multi-organ failure is most likely to be autoimmune in nature and that strategies to counter these multifacet autoimmune disorders would be the most valuable in life-saving. Specifically, we identified clinical and laboratory evidence pointing to IgA autoimmune reaction as a key factor that causes significant mortality in many patients. Accordingly, we proposed the utilization of a combination of dapsone, corticosteroid, and anti-thrombotic drugs in severely ill patients at the earliest point of the disease process. The autoimmune multi-organ syndrome may explain the pathogenesis of COVID-19 as well as Post-COVID conditions and may guide healthcare professionals in a better direction to manage the disease. The possible origin of the viral pathogen may shed light on a better understanding of the pathogenesis of the disease.

Comparison of epidemiological characteristics COVID-19 Delta variant infection among children in Xi'an and Baoji

Objective:To explore the epidemiological characteristics of Corona Virus Disease 2019(COVID-19)Delta variant infection in children in Xi'an and Baoji.Methods:According to the official information released by Shaanxi Province,the information of confirmed cases in Xi'an(December 20,2021 to January 8,2022)and Baoji(March 8 to March 27,2022)were collected respectively.Records include age,sex,residential address,community and other basic information.Isolation mode,isolation time,morbidity and positive time of viral nucleic acid test,vaccination,clinical typing,close contact personnel,cluster incidence situation and the social activity tracking of the confirmed cases were collected,and the data were statistically analyzed.Results:In 20 days,there were 281 infected children in Xi'an,accounting for 14.48%of the total cases(1,940 cases),including 154 boys(54.8%)and 127 girls(45.20%).The number of diagnosed children in Baoji City(55 cases)is 19.57%of that in Xi'an(55/281),but accounts for 23.31%of the total number of cases(236 cases)in Baoji(this ratio is higher than that of 14.48%in Xi'an).Among the 55 cases of children,there are 33 males(60.00%)and 22 females(40.00%).The proportion of male children in both cities is higher.The median age of diagnosed children in Xi'an was 7.0 years(IQR:1.0-13.0 years old),and the age range was 4 d-18 years old,while the median age of Baoji children was 9.0 years old(IQR:5.0-17.0 years old),ranging from 3 months to 18 years old.The number of children vaccinated in Xi'an and Baoji was positively correlated with the number of infected children.The vaccination rates of children in Xi'an and Baoji were 64.06%and 52.73%,respectively.The vaccination rates of infants(≤1 year old)in both cities were 18.52%and 14.29%,respectively.On the whole,the number of new child cases in the two cities increased first and then decreased.The peak number of new child cases in Xi'an was 39(10th day of statistics),while that of Baoji was 13(6th day of statistics).The peak in Xi'an comes later and the epidemic lasts longer.Among the children in Xi'an,201(71.53%)had a history of close contact,55(19.57%)had no clear history of COVID-19 infection,and were positive after actively participating in the nucleic acid test of all members of the community,of which 54(98.18%)were primary and middle school students.54 cases(98.18%)of Baoji children had a history of close contact,of which 20 cases were infected by the confirmed case number 62 officially announced on March 10.The time to be positive for viral nucleic acid test in children after isolation was 1-14 days.The positive rate of children in Xi'an reached 85.41%(240/281)after 7 days of isolation,and the highest peak of positive detection was on the third day of isolation(84 cases).After 7 days of isolation,45 cases were positive in Baoji,accounting for 81.82%(45/55).The highest peak of positive detection was on the 5th day of isolation(11 cases).The regional distribution of infected children in Xi'an was the highest in Yanta District(137 cases),followed by High-tech Zone(42 cases)and Lianhu District(29 cases).The main manifestations of COVID-19 in Xi'an were light(278 cases,98.93%),common type(3 cases,1.07%),light in Baoji(54 cases,98.18%),and common type(1 case,1.82%).Through general clinical treatment(including traditional Chinese medicine treatment and symptomatic treatment),all were cured.Conclusion:Delta variant increases the susceptibility of children to infection,which spreads rapidly mainly through close family contact and community concealment,so it is necessary to study better early diagnosis and prevention and control measures.

Dynamic evolution of an SVEIR model with variants and non-pharmaceutical interventions for controlling COVID-19

The epidemiological characteristics and distributions of two epidemics in Fujian Province of Southeast China were attributed to the complex interactions among variant,host,and non-pharmaceutical interventions(NPIs).All reported cases in the Putian epidemic(September 8–October 2,2021,Delta variant B.1.617.2)and Fuzhou epidemic(October 22–November 18,2022,Omicron variant BA.5.2)were classified by sex,age group,occupation,and location in this study.Using surveillance data from the Fujian Provincial Center for Disease Control and Prevention,we established a virus-oriented SVEIR(Susceptible–Vaccinated–Exposed–Infected–Recovered)model to investigate the dynamic evolution features of these two variants and the effects of NPIs.The optimal simulations were carried out with variants and scenario investigations.The scenario investigations showed that NPIs significantly reduced the transmission risk and infection scales of COVID-19,and that the Omicron variant was more infectious than the Delta variant.Moreover,the dynamic investigations revealed the increasing tendencies from Delta to Omicron,such as the basic reproduction number,infection rate,percentage of high-risk cases,and the growth rate.Decreasing tendencies were also identified,such as the average recovery period,the awareness delay,and the percentage of symptomatic cases.This study highlighted that NPIs played critical roles in successfully containing the two epidemics.Such interventions are strongly recommended to public health policymakers.

A Severe COVID-19 Infection in Neonates: A Case Report

Coronavirus disease (COVID-19) is a highly contagious infectious disease. First case was reported at the end of 2019 in China. Children and neonate population appears to be relatively free of the virus. We reported a severe and fatal neonate case of COVID-19 in a 22 days old neonate female due to the delta variant strain during the third wave outbreak. She presented with fever, cough, grunting and diarrhea started 5 days before admission. Physical exam’s revealed severe respiratory distress, hypoxia and bilateral pulmonary condensation. PCR test for COVID-19 was positive. Chest X-ray found bilateral infiltrates. Chest CT showed diffuse ground glass images with 75% of lung parenchymal involvement. She was treated with antibiotics, corticostoid, respiratory support (CPAP and oxygen). Death occurred after 15 days of hospitalization in the context of multiple organ failure and pulmonary hypertension.

Covid Pneumonitis Presenting as Intractable Hiccups

Background: Hiccups, also known as Singletus, can be a cause of worry and anxiety for most patients when persistent. It has long been associated with various infectious pathologies. Its association with SARS-COV-19 is relatively new with only a few cases reported so far. This case report highlights a unique presentation of Covid pneumonitis as intractable hiccups as the only symptom. With adequate laboratory and instrumental investigations, the aetiology was found to be Covid pneumonitis. Once the cause was detected and treatment initiated, the symptoms subsided. Conclusion: While hiccup can be a sign of various underlying chronic illnesses, its association with Covid-19 is relatively new with very few literatures reporting this finding. It is very crucial for clinicians to keep a high index of suspicion in patients presenting with hiccups.

Mathematical modeling for Delta and Omicron variant of SARS-CoV-2 transmission dynamics in Greece

A compartmental,epidemiological,mathematical model was developed in order to analyze the transmission dynamics of Delta and Omicron variant,of SARS-CoV-2,in Greece.The model was parameterized twice during the 4th and 5th wave of the pandemic.The 4th wave refers to the period during which the Delta variant was dominant(approximately July to December of 2021)and the 5th wave to the period during which the Omicron variant was dominant(approximately January to May of 2022),in accordance with the official data from the National Public Health Organization(NPHO).Fitting methods were applied to evaluate important parameters in connection with the transmission of the variants,as well as the social behavior of population during these periods of interest.Mathematical models revealed higher numbers of contagiousness and cases of asymptomatic disease during the Omicron variant period,but a decreased rate of hospitalization compared to the Delta period.Also,parameters related to the behavior of the population in Greece were also assessed.More specifically,the use of protective masks and the abidance of social distancing measures.Simulations revealed that over 5,000 deaths could have been avoided,if mask usage and social distancing were 20%more efficient,during the short period of the Delta and Omicron outbreak.Furthermore,the spread of the variants was assessed using viral load data.The data were recorded from PCR tests at 417 Army Equity Fund Hospital(NIMTS),in Athens and the Ct values from 746 patients with COVID-19 were processed,to explain transmission phenomena and disease severity in patients.The period when the Delta variant prevailed in the country,the average Ct value was calculated as 25.19(range:12.32e39.29),whereas during the period when the Omicron variant prevailed,the average Ct value was calculated as 28(range:14.41e39.36).In conclusion,our experimental study showed that the higher viral load,which is related to the Delta variant,may interpret the severity of the disease.However,no correlation was confirmed regarding contagiousness phenomena.The results of the model,Ct analysis and official data from NPHO are consistent.

Chest CT features of children infected by B.1.617.2 (Delta) variant of COVID‑19

Background This study aimed to explore the imaging characteristics,diversity and changing trend in CT scans of pediatric patients infected with Delta-variant strain by studying imaging features of children infected with Delta and comparing the results to those of children with original COVID-19.Methods A retrospective,comparative analysis of initial chest CT manifestations between 63 pediatric patients infected with Delta variant in 2021 and 23 pediatric patients with COVID-19 in 2020 was conducted.Corresponding imaging features were analyzed.In addition,the changing trend in imaging features of COVID-19 Delta-variant cases were explored by evaluating the initial and follow-up CT scans.Results Among 63 children with Delta-variant COVID-19 in 2021,34(53.9%)showed positive chest CT presentation;and their CT score(1.10±1.41)was signifcantly lower than that in 2020(2.56±3.5)(P=0.0073).Lesion distribution:lung lesions of Delta cases appear mainly in the lower lungs on both sides.Most children had single lobe involvement(18 cases,52.9%),14(41.2%)in the right lung alone,and 14(41.2%)in both lungs.A majority of Delta cases displayed initially ground glass(23 cases,67.6%)and nodular shadows(13 cases,38.2%)in the frst CT scan,with few extrapulmonary manifestations.The 34 children with abnormal chest CT for the frst time have a total of 92 chest CT examinations.These children showed a statistically signifcant diference between the 0-3 day group and the 4-7 day group(P=0.0392)and a signifcant diference between the 4-7 day group and the more than 8 days group(P=0.0003).Conclusions The early manifestations of COVID-19 in children with abnormal imaging are mostly small subpleural nodular ground glass opacity.The changes on the Delta-variant COVID-19 chest CT were milder than the original strain.The lesions reached a peak on CT in 4-7 days and quickly improved and absorbed after a week.Dynamic CT re-examination can achieve a good prognosis.

Increased pathogenicity and aerosol transmission for one SARS-CoV-2 B.1.617.2 Delta variant over the wild-type strain in hamsters

During the two-year pandemic of coronavirus disease 2019(COVID-19), its causative agent, severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), has been evolving. SARS-CoV-2 Delta, a variant of concern, has become the dominant circulating strain worldwide within just a few months. Here, we performed a comprehensive analysis of a new B.1.617.2 Delta strain(Delta630) compared with the early WIV04 strain(WIV04) in vitro and in vivo, in terms of replication, infectivity, pathogenicity, and transmission in hamsters. When inoculated intranasally, Delta630 led to more pronounced weight loss and more severe disease in hamsters. Moreover, 40%mortality occurred about one week after infection with 10^(4)PFU of Delta630, whereas no deaths occurred even after infection with 10^(5)PFU of WIV04 or other strains belonging to the Delta variant. Moreover, Delta630outgrew over WIV04 in the competitive aerosol transmission experiment. Taken together, the Delta630 strain showed increased replication ability, pathogenicity, and transmissibility over WIV04 in hamsters. To our knowledge, this is the first SARS-CoV-2 strain that causes death in a hamster model, which could be an asset for the efficacy evaluation of vaccines and antivirals against infections of SARS-CoV-2 Delta strains. The underlying molecular mechanisms of increased virulence and transmission await further analysis.

Inhaled heparin polysaccharide nanodecoy against SARS-CoV-2 and variants

To the Editor:As of January 27,2022,there were 363,062,293 cases and 5,645,884deaths from the COVID-19 pandemic1.The prevalent mutated strains have aggravated the global pandemic2.SARS-Co V-2 is highly mutable,and the mutations on the spike(S)protein resulted in a high transmission of COVID-19 and vaccine breakthrough infection3.For example,there is a notable decrease in neutralizing ability of BNT162b2 vaccination-elicited antibodies against the Delta and other variants4,5,and attenuation of peak viral burden and vaccine effectiveness are reduced with Delta variant6.

Clinical and immune response characteristics among vaccinated persons infected with SARS-CoV-2 delta variant:a retrospective study

Objective:This study aimed to observe the clinical and immune response characteristics of vaccinated persons infected with the delta variant of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)in Yangzhou,China.Methods:We extracted the medical data of 129 patients with delta-variant infection who were admitted to Northern Jiangsu People’s Hospital(Yangzhou,China)between August and September,2021.The patients were grouped according to the number of vaccine doses received into an unvaccinated group:a one-dose group and a two-dose group.The vaccine used was SARS-CoV-2-inactivated vaccine developed by Sinovac.We retrospectively analyzed the patients’epidemiological,clinical,laboratory,and imaging data.Results:Almost all patients with delta-variant infection in Yangzhou were elderly,and patients with severe/critical illness were over 70 years of age.The rates of severe/critical illness(P=0.006),fever(P=0.025),and dyspnea(P=0.045)were lower in the two-dose group than in the unvaccinated group.Compared to the unvaccinated group,the two-dose group showed significantly higher lymphocyte counts and significantly lower levels of C-reactive protein(CRP),interleukin-6(IL-6),and D-dimer during hospitalization and a significantly higher positive rate of immunoglobulin G(IgG)antibodies at admission(all P<0.05).The cumulative probabilities of hospital discharge and negative virus conversion were also higher in the two-dose group than in the unvaccinated group(P<0.05).Conclusions:Two doses of the SARS-CoV-2-inactivated vaccine were highly effective at limiting symptomatic disease and reducing immune response,while a single dose did not seem to be effective.

Screening for inhibitors against SARS-CoV-2 and its variants

Severe acute respiratory syndrome coronavirus 2(SARS‐CoV‐2)continues to evolve,generating new variants that pose a threat to global health;therefore,it is imperative to obtain safe and broad‐spectrum antivirals against SARS‐CoV‐2 and its variants.To this end,we screened compounds for their ability to inhibit viral entry,which is a critical step in virus infection.Twenty compounds that have been previously reported to inhibit SARS‐CoV‐2 replication were tested by using pseudoviruses containing the spike protein from the original strain(SARS‐CoV‐2‐WH01).The cytotoxicity of these compounds was determined.Furthermore,we identified six compounds with strong antagonistic activity against the WH01 pseudovirus,and low cytotoxicity was identified.These compounds were then evaluated for their efficacy against pseudoviruses expressing the spike protein from B.1.617.2(Delta)and B.1.1.529(Omicron),the two most prevalent circulating strains.These assays demonstrated that two phenothiazine compounds,trifluoperazine 2HCl and thioridazine HCl,inhibit the infection of Delta and Omicron pseudoviruses.Finally,we discovered that these two compounds were highly effective against authentic SARS‐CoV‐2 viruses,including the WH01,Delta,and Omicron strains.Our study identified potential broad‐spectrum SARS‐CoV‐2 inhibitors and provided insights into the development of novel therapeutics.

A follow up study of cycle threshold values of SARS-CoV-2 in Hunan Province,China

Since the epidemic of the severe acute respiratory syndrome coronavirus 2(SARS-COV-2),many governments have used reverse transcription polymerase chain reaction(RT-PCR)to detect the virus.However,there are fewer measures of CT values information based on RT-PCR results,and the relationship between CT values and factors from consecutive tests is not clear enough.So in this study,we analyzed the connection between CT values and the factors based on cohort data from Delta variant of SARS-CoV-2 in Hunan Province.Previous studies have showed that the mean age of the cases was 33.34 years(±18.72 years),with a female predominance(55.03%,n=71),and the greatest proportion of clinical symptoms were of the common type(60.47%,n=78).There were statistical differences between the N and ORF1ab genes in the CT values for the cases.Based on the analysis of the association between CT values and the factors,the lowest CT values were obtained for the unvaccinated,older and clinically symptomatic group at 3e10 days,the maximum peak of viral load occurred.Therefore,it is recommended to use patient information to focus on older,clinically symptomatic,unvaccinated patients and to intervene promptly upon admission.

Quantifying competitive advantages of mutant strains in a population involving importation and mass vaccination rollout

The SARS-CoV-2 Delta variant,known as B.1.617.2 and first identified in India,is becoming a dominant strain in many countries due to its extreme infectiousness.Assessing and quantifying the transmissibility and competitive advantage of the Delta variant is of major significance for countries around the world so that appropriate measures to mitigate and even eliminate the epidemic can be introduced.Aiming at such problems,we proposed a method to model the invasion process of a novel strain and estimate the competitive advantage of the invading strain over the local strain.We applied this method to study the invasion and spread of the Delta variant into England.We have estimated the basic reproduction number of the Delta variant as being 49%higher than that of the Alpha variant(CI:45-52%),assuming a mean generation interval of 5 days with a standard deviation of 3 days.In the period 11 April to 17 May 2021,the effective reproduction number of the Delta variant was 65%higher than that of the Alpha variant in England(CI:61-70%).Our results show that the Delta variant has a significantly higher transmission capacity than other strains,which explains the rebound of the epidemic in many countries,even in those with relatively high vaccination coverages.

Global trends in COVID-19

The pandemic COVID-19 is certainly one of the most severe infectious diseases in human history.In the last 2 years,the COVID-19 pandemic has caused over 418.6 million confirmed cases and 5.8 million deaths world-wide.Young people make up the majority of all infected COVID-19 cases,but the mortality rate is relatively lower compared to older age groups.Currently,about 55.04%individuals have been fully vaccinated rapidly approaching to herd immunity globally.The challenge is that new SARS-CoV-2 variants with potential to evade immunity from natural infection or vaccine continue to emerge.Breakthrough infections have occurred in both SARS-CoV-2 naturally infected and vaccinated individuals,but breakthrough infections tended to exhibit mild or asymptomatic symptoms and lower mortality rates.Therefore,immunity from natural infection or vaccination can reduce SARS-CoV-2 pathogenicity,but neither can completely prevent SARS-CoV-2 infection/reinfection.Fortunately,the morbidity and mortality of COVID-19 continue to decline.The 7-day average cumulative case fatality of COVID-19 has decreased from 12.3%on the February 25,2020,to 0.27%on January 09,2022,which could be related to a decreased SARS-CoV-2 variant virulence,vaccine immunization,and/or better treatment of patients.In conclusion,elimination of SARS-CoV-2 in the world could be impossible or at least an arduous task with a long way to go.The best strategy to prevent COVID-19 pandemic is to expand inoculation rate of effective vaccines.As the population reaches herd immunity,the mortality rate of COVID-19 may continue to decrease,and COVID-19 could eventually become another common cold.