Clinical features of children with coronavirus disease 2019 caused by Delta variant infection in different age groups / 中国当代儿科杂志

OBJECTIVES@#To study the clinical features of children with coronavirus disease 2019 (COVID-19) caused by Delta variant infection in different ages groups.@*METHODS@#A total of 45 children with COVID-19 caused by Delta variant infection who were hospitalized in the designated hospital in Henan Province, China, from November 17 to December 17, 2021, were included. They were divided into three groups: <6 years group (n=16), 6-13 years group (n=16), and >13 years group (n=13). The three groups were compared in clinical features and laboratory examination data.@*RESULTS@#COVID-19 in all age groups was mainly mild. Main manifestations included cough and expectoration in the three groups, and fever was only observed in the 6-13 years group. The <6 years group had significantly higher serum levels of aspartate aminotransferase, lactate dehydrogenase, and creatine kinase isoenzymes than the other two groups (P<0.05). The 6-13 years group had the highest proportion of children with elevated serum creatinine levels (50%). Among the three groups, only 4 children in the >13 years group had an increase in serum C-reactive protein levels. The 6-13 years group had the lowest counts of CD3+CD4+ lymphocytes, CD3+CD8+ lymphocytes, and natural killer cells in the peripheral blood among the three groups. The >13 years group had a significantly higher positive rate of SARS-CoV-2 IgG on admission than the other two groups (P<0.05). There was no significant difference in the imaging findings on chest CT among the three groups (P>0.05).@*CONCLUSIONS@#The clinical features of COVID-19 caused by Delta variant infection in children of different age groups may be different: children aged <6 years tend to develop myocardial injury, and those aged 6-13 years have fever except cough and expectoration and tend to develop renal and immune dysfunction.

Construction and immunogenicity evaluation of SARS-Co V-2 self-amplifying RNA vaccine based on Coxsackievirus-A5 replicon / 中国生物制品学杂志

@#ObjectiveTo construct self-amplifying RNA(saRNA)vaccine of severe acute respiratory syndrome coronavirus2(SARS-CoV-2)Delta mutant strain(B.1.617.2)based on Coxsackievirus-A5(CV-A5)replicon and evaluate its immunogenicity.MethodsThe recombinant plasmids pDelta-S10,pDelta-S5 and pDelta-S1(10,5 and 1 amino acid residues at the upstream of S-VP1/2A cleavage site of the fusion polyprotein respectively)were constructed by In-fusion cloning of the plasmids containing the full-length genome sequence of CV-A5 and substituting the S protein gene of SARS-CoV-2 Delta mutant for the P1 structural protein gene of CV-A5 with different lengths.Three RNA molecules,Delta-S10,Delta-S5 and Delta-S1,were obtained by in vitro transcription of linearized recombinant plasmids and transfected into HEK-293T cells respectively,which were analyzed for the expression of S protein by Western blot.The RNA molecule with the highest expression of S protein was screened out and detected for the self-amplification in HEK-293T cells by qPCR.BALB/c mice(female,6 ～ 8 weeks old and five for each group)were immunized i.m.with two doses(0.5 and 2.5 μg)of the screened Delta-S packaged with lipid nanoparticles for once on day 1 and day 14 seperately.Blood samples were collected on days 14and 28,detected for serum binding antibody titers by ELISA,and detected for neutralizing antibody titers by micro neutralization method.The spleens were harvested on day 42 and detected for the level of IFNγ secreted by mouse spleen cells by enzyme linked enzyme linked immunospot assay(ELISPOT).ResultsThe recombinant RNA molecule Delta-S10showed the highest expression of S protein and self-amplified in HEK-293T cells,which of both high and low doses induced specific binding antibody against SARS-CoV-2 Delta S1 protein in mice with obvious dose effect and enhanced immune effect;The high dose of Delta-S10 induced neutralizing antibodies and cellular immune responses in mice.ConclusionThe SARS-CoV-2 Delta mutant(B.1.617.2)saRNA vaccine Delta-S10 based on CV-A5 replicon was successfully constructed,which induced humoral and cellular immune responses in mice,laying a foundation of the further study of the construction of SARS-CoV-2 saRNA vaccine by enterovirus replication elements.

Characterizing the third wave of COVID-19: An analysis from the National Clinical Registry of COVID-19

Background & objectives: Data from the National Clinical Registry for COVID-19 (NCRC) were analyzed with an aim to describe the clinical characteristics, course and outcomes of patients hospitalized with COVID-19 in the third wave of the pandemic and compare them with patients admitted earlier. Methods: The NCRC, launched in September 2020, is a multicentre observational initiative, which provided the platform for the current investigation. Demographic, clinical, treatment and outcome data of hospitalized COVID-19 patients were captured in an electronic data portal from 38 hospitals across India. Patients enrolled during December 16, 2021 to January 17, 2022 were considered representative of the third wave of COVID-19 and compared with those registered during November 15 to December 15, 2021, representative of the tail end of the second wave. Results: Between November 15, 2021 and January 17, 2022, 3230 patients were recruited in NCRC. Patients admitted in the third wave were significantly younger than those admitted earlier (46.7±20.5 vs. 54.6±18 yr). The patients admitted in the third wave had a lower requirement of drugs including steroids, interleukin (IL)-6 inhibitors and remdesivir as well as lower oxygen supplementation and mechanical ventilation. They had improved hospital outcomes with significantly lower in-hospital mortality (11.2 vs. 15.1%). The outcomes were better among the fully vaccinated when compared to the unvaccinated or partially vaccinated.Interpretation & conclusions: The pattern of illness and outcomes were observed to be different in the third wave compared to the last wave. Hospitalized patients were younger with fewer comorbidities, decreased symptoms and improved outcomes, with fully vaccinated patients faring better than the unvaccinated and partially vaccinated ones.

Neutralization assays for SARS-CoV-2: Implications for assessment of protective efficacy of COVID-19 vaccines

The WHO emergency use-listed (EUL) COVID-19 vaccines were developed against early strains of SARS-CoV-2. With the emergence of SARS-CoV-2 variants of concern (VOCs) - Alpha, Beta, Gamma, Delta and Omicron, it is necessary to assess the neutralizing activity of these vaccines against the VOCs. PubMed and preprint platforms were searched for literature on neutralizing activity of serum from WHO EUL vaccine recipients, against the VOCs, using appropriate search terms till November 30, 2021. Our search yielded 91 studies meeting the inclusion criteria. The analysis revealed a drop of 0-8.9-fold against Alpha variant, 0.3-42.4-fold against Beta variant, 0-13.8-fold against Gamma variant and 1.35-20-fold against Delta variant in neutralization titres of serum from the WHO EUL COVID-19 vaccine recipients, as compared to early SARS-CoV-2 isolates. The wide range of variability was due to differences in the choice of virus strains selected for neutralization assays (pseudovirus or live virus), timing of serum sample collection after the final dose of vaccine (day 0 to 8 months) and sample size (ranging from 5 to 470 vaccinees). The reasons for this variation have been discussed and the possible way forward to have uniformity across neutralization assays in different laboratories have been described, which will generate reliable data. Though in vitro neutralization studies are a valuable tool to estimate the performance of vaccines against the backdrop of emerging variants, the results must be interpreted with caution and corroborated with field-effectiveness studies.

Clinical characteristics of imported patients infected with 2019 novel coronavirus Omicron variants and Delta variants in Guangzhou City / 中华传染病杂志

Objective:To analyze and compare the clinical characteristics and prognosis of imported patients infected with 2019 novel coronavirus (2019-nCoV) Omicron variants and Delta variants, so as to provide references for clinical diagnosis, treatment and epidemic prevention strategies.Methods:The patients with imported 2019-nCoV infection from August 1, 2021 to January 18, 2022 in Guangzhou Eighth People′s Hospital, Guangzhou Medical University were retrospectively analyzed. According to the whole genome sequencing of 2019-nCoV in nasal or throat swabs, they were divided into Omicron group and Delta group. The clinical characteristics, laboratory tests, antibody levels, viral nucleic acid (the cycle threshold (Ct) of N gene and open reading frame ( ORF) 1 ab), main treatment measures and clinical prognosis were analyzed in the two groups. Statistical analysis was performed using the rank sum test, chi-square test or Fisher′s exact test. Results:A total of 344 cases were enrolled, including 152 cases in the Delta group and 192 cases in the Omicron group, and there were 240 males (69.8%), with a median age of 33 years old. One hundred and two (29.7%) of those patients had underlying disease.Two hundred and seventy-one had completed full or booster vaccination. The overall full vaccination rate in Omicron group was 70.8%(136/192), which was higher than 51.3%(78/152) in Delta group. The proportion of mild patients in Omicron group was higher than that in Delta group (57.3%(110/192) vs 24.3%(37/152), respectively), and the proportions of common type and severe type were lower than those of the Delta group (33.9%(65/192) vs 55.3%(84/152) and 0(0/192) vs 10.5%(16/152)), the differences were all statistically significant ( χ2=37.64 and 15.84, respectively, Fisher′s exact test; all P<0.001). The duration and peak of fever in Omicron group were 1.5(1.0, 2.0) d and 38.1(37.8, 38.5) ℃, respectively, which were lower than those in Delta group (3.0(1.0, 4.8) d and 38.5(38.1, 39.0) ℃, respectively), and the differences were both statistically significant ( Z=-4.14 and -3.85, respectively, both P<0.001). The 2019-nCoV antibody IgG and the Ct values of virus nucleic acid N gene and ORF1 ab gene in the vaccinated Omicron group at admission were higher than those in the Delta group ( Z=-3.25, -2.18 and -2.82, respectively, all P<0.050). Compared with patients in Delta group, patients in Omicron group had lower proportion of receiving respiratory therapy support, shorter oxygen therapy time, shorter reversion time from admission to nucleic acid Ct value≥35 and shorter hospitalization time. The differences were all statistically significant ( χ2=47.86, Z=-5.41, -5.60 and -4.71, respectively, all P<0.001). There was no critical illness or 28-day death case in both groups. Conclusions:The severity of patients infected with Omicron variants is lighter than that of patients with Delta variants, and the viral nucleic acid has shorter conversion time, which is mainly related to the virulence of variant strain and vaccination.

Critical coronavirus disease 2019 caused by Delta variant: a case report with literature review / 中华危重病急救医学

Objective:To investigate the curative efficacy and application value of convalescent plasma (CP)in severe and critical coronavirus disease 2019 (COVID-19) caused by Delta variant.Methods:The treatment process and results of CP therapy for a patient with critical COVID-19 caused by Delta variant were reported. The clinical application value of CP for COVID-19 caused by Delta variant was analyzed along with the literature review.Results:Our case was a 50-year-old male, who was imported from abroad and had not been vaccinated against COVID-19. The novel coronavirus nucleic acid test was negative before entry. On the second day after entry, fever occurred, novel coronavirus nucleic acid test was positive. Chest CT images showed bilateral multiple mottling and ground-glass opacity with symptoms of nausea, headache, loss of appetite, diarrhea, but no running nose, nasal obstruction, dyspnea, abnormal smell and taste. The infection rapidly developed from medium to critical. On the basis of standard treatment, Delta variant CP was intravenous dripped on the 10th day of hospital admission (the 6th day after becoming severe). The patient's condition improved rapidly.Conclusion:The curative efficacy evaluation of this patient proved that CP therapy is of great value in the treatment of severe and critical COVID-19.

Follow-up of patients with COVID-19 by the Delta variant after hospital discharge in Guangzhou, Guandong, China

ABSTRACT The B.1.617.2 (Delta) variant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has contributed to a new increment in cases across the globe. We conducted a prospective follow-up of COVID-19 cases to explore the recurrence and potential propagation risk of the Delta variant and discuss potential explanations for the infection recurrence. A prospective, non-interventional follow-up of discharged patients who had SARS-CoV-2 infections by the Delta variant in Guangdong, China, from May 2021 to June 2021 was conducted. The subjects were asked to complete a physical health examination and undergo nucleic acid testing and antibody detection for the laboratory diagnosis of COVID-19. In total, 20.33% (25/123) of patients exhibited recurrent positive results after discharge. All patients with infection recurrence were asymptomatic and showed no abnormalities in the pulmonary computed tomography. The time from discharge to the recurrent positive testing was usually between 1-33 days, with a mean time of 9.36 days. The cycle threshold from the real-time polymerase chain reaction assay that detected the recurrence of positivity ranged from 27.48 to 39.00, with an average of 35.30. The proportion of vaccination in the non-recurrent group was higher than that in the recurrently positive group (26% vs. 4%; χ2 = 7.902; P < 0.05). Two months after discharge, the most common symptom was hair loss and 59.6% of patients had no long-term symptoms at all. It is possible for the Delta variant SARS-CoV-2 patients after discharge to show recurrent positive results of nucleic acid detection; however, there is a low risk of continuous community transmission. Both, the physical and mental quality of life of discharged patients were significantly affected. Our results suggest that it makes sense to implement mass vaccination against the Delta variant of SARS-CoV-2.

Generation of neutralizing antibodies against Omicron, Gamma and Delta SARS-CoV-2 variants following CoronaVac vaccination

ABSTRACT Vaccination is a fundamental tool to prevent SARS-CoV-2 infection and to limit the COVID-19 pandemic. The emergence of SARS-CoV-2 variants with multiple mutations has raised serious concerns about the ability of neutralizing antibody responses elicited by prior vaccination to effectively combat these variants. The neutralizing capacity against the Gamma, Delta and Omicron variants of sera from individuals immunized with the CoronaVac vaccine remains incompletely determined. The present study evaluated 41 health care workers at the Faculdade de Medicina of the Universidade de Sao Paulo, in Sao Paulo, Brazil, naive to previous SARS- CoV-2 infection, who were vaccinated with two doses of the CoronaVac SARS-CoV-2 vaccine 28 days apart. Neutralizing antibody levels against the Gamma, Delta, and Omicron variants were measured at 32 and 186 days after the second vaccination. We also measured neutralizing antibodies against Omicron in 34 of these individuals following a subsequent booster immunization with the Pfizer vaccine. Quantification of neutralizing antibodies was performed using the Cytopathic Effect-based Virus Neutralization test. Neutralization antibody activity against the Gamma, Delta and Omicron variants was observed in 78.0%, 65.9% and 58.5% of serum samples, respectively, obtained at a mean of 32 days after the second immunization. This decreased to 17.1%, 24.4% and 2.4% of sera having activity against Delta, Gamma and Omicron, respectively, at 186 days post-vaccination. The median neutralizing antibody titers at 32 days were 1:40, 1:20 and 1:20 against Gamma, Delta and Omicron, respectively, and decreased to an undetectable median level against all variants at the later time. A booster immunization with the Pfizer vaccine elicited neutralizing antibodies against Omicron in 85% of subjects tested 60 days after vaccination. We conclude that two doses of the CoronaVac vaccine results in limited protection of short duration against the Gamma, Delta and Omicron SARS-CoV-2 variants. A booster dose with the Pfizer vaccine induced antibody neutralizing activity against Omicron in most patients which was measurable 60 days after the booster.

A comparative study of vaccination with inactivated SARS-COV-2 vaccine on the clinical manifestations and serological responses of COVID-19 patients infected by Delta and Alpha variants / 中国热带医学

@#Abstract: Objective　To investigate the impacts of vaccination with inactivated SARS-COV-2 vaccine on the clinical manifestations and serological responses of COVID-19 patients infected by Delta and Alpha variants. Methods　Clinical and experimental data of 341 confirmed SARS-COV-2 patients were collected from The Eighth Affiliated Hospital of Guangzhou Medical University May 1- September 30, 2021. The subjects were divided into Delta and Alpha variant group according to virus variants, and were divided into vaccinated group and unvaccinated group according to whether they had received inactivated COVID-19 vaccine or not. The clinical manifestations and serological responses of patients with Delta and Alpha variant, and vaccinated and unvaccinated patients with Delta and Alpha variants were compared. Results　Totally 253 patients were infected with Delta variant (103 vaccinated and 150 unvaccinated patients), and 88 patients were infected with Alpha variant (21 vaccinated and 67 unvaccinated patients). The proportion of asymptomatic infection in Delta variants group was significantly lower than that in Alpha variants group (P<0.01). Delta variant group of vaccination rates and vaccine breakthrough infection rate was 40.7% (103/253) and 22.9% (58/253), were higher than Alpha variant group was 23.9% (21/88) and 8.0% (7/88), difference was statistically significant (χ2= 8.009, 9.484, P<0.01). The proportion of cough and fever in Delta variant group was higher than that in Alpha variant group (both P<0.01), the peak viral load was higher than that of Alpha variant group (P<0.01), the virus duration was longer than that of Alpha variant group (P<0.01), the levels of SAA, CRP and IFN were higher than those of Alpha variant group (all P<0.05), CD4+T cell count was lower than that of Alpha variant group (P<0.05), IgG and IgM levels were lower than those of Alpha variant group (both P<0.01). The proportion of moderate COVID-19 in the vaccinated group was lower than that in the unvaccinated group (P<0.01). In these two variants, the peak viral load of vaccinated group was lower than that of the unvaccinated group (both P<0.01), the duration of virus was shorter than that of unvaccinated group (both P<0.01). The levels of SAA, CRP and IL-6 in the vaccinated group were lower than those in the unvaccinated group (all P<0.05), CD4+T cell level was higher than that of unvaccinated group (both P<0.05), IgG and IgM level were higher than those in unvaccinated group (both P<0.05). Conclusions　Delta variant can lead to higher viral load and more severe disease course, which is associated with vaccine breakthrough infection. Inactivated vaccines for COVID-19 can reduce severe illness and death by reducing viral load, disease duration and inflammatory response through humoral and cellular immune mechanisms.

Genome characterization and traceability analysis of SARS-CoV-2 in a local outbreak / 中华微生物学和免疫学杂志

Objective:To analyze the genome characteristics and variations in nucleotides and amino acids of SARS-CoV-2 causing an outbreak in Henan Province in November 2021 and perform the traceability analysis.Methods:In this study, throat swab specimens from cases in the acute phase were collected and tested for the nucleic acids of SARS-CoV-2 by real-time fluorescent RT-PCR. SARS-CoV-2 nucleic acid-positive samples were subjected to high-throughput genome sequencing and whole-genome alignment analysis.Results:The median Ct values of ORF1ab gene and N gene in 70 positive specimens was 26.41 (15.58 to 39.27) and 24.43 (12.04 to 39.74), respectively. Compared with the sequence of Wuhan-Hu(NC_045512) reference strain, 47 to 49 nucleotide mutations sharing 47 nucleotide mutation and 41 amino acid mutations were found in 63 strains of successfully sequenced SARS-CoV-2. Nine nucleotide mutations and 12 amino acid mutations were found in the spike protein. The index case shared 47 mutations with the Russian imported cases in Henan Province on October 14 and the local cases in Jiangxi Province in October. Moreover, their genomes were highly homologous and they all belonged to the Delta variant (AY.122 evolutionary branch).Conclusions:Continuous monitoring of imported COVID-19 cases and prolonging the period of quarantine were needed to reduce the risk of local outbreak and epidemic caused by imported COVID-19 cases. Analysis of the genomic characteristics of SARS-CoV-2 and the variations in nucleotides and amino acids was conducive to trace the origin of COVID-19 outbreak quickly and provide reference for precise control.

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

The heparin polysaccharide nanoparticles block the interaction between heparan sulfate/S protein and inhibit the infection of both wild-type SARS-CoV-2 pseudovirus and the mutated strains through pulmonary delivery.Image 1.

Clinical features of children with coronavirus disease 2019 Delta variant infection after vaccination with inactivated SARS-CoV-2 vaccine / 中国当代儿科杂志

OBJECTIVES@#To study the clinical features of children with coronavirus disease 2019 (COVID-19) Delta variant infection vaccinated or not vaccinated with inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine.@*METHODS@#A total of 11 children with COVID-19 Delta variant infection who were vaccinated with inactivated SARS-CoV-2 vaccine and were hospitalized in the designated hospital in Henan Province, China, from November 3 to December 17, 2021 were enrolled as the vaccinated group. Thirty-one children with COVID-19 Delta variant infection who were not vaccinated and were hospitalized during the same period were enrolled as the unvaccinated group. A retrospective analysis was performed on their epidemiological data, clinical features, and laboratory examination results.@*RESULTS@#There was no significant difference in gender composition and disease classification between the two groups (P>0.05), and there was also no significant difference in the incidence rates of the clinical symptoms such as cough, expectoration, and fever between the two groups (P>0.05). No significant difference was found between the two groups in leukocyte count, lymphocyte percentage, alanine aminotransferase, and serum creatinine (P>0.05). Compared with the unvaccinated group, the vaccinated group had significantly lower levels of aspartate aminotransferase, lactate dehydrogenase, and creatine kinase-MB (P<0.05). There was no significant difference between the two groups in the proportion of children with elevated C-reactive protein or procalcitonin and the levels of peripheral blood cytokines (P>0.05). The vaccinated group had significantly lower counts of B lymphocytes and total T lymphocytes (CD3+) than the unvaccinated group (P<0.05). Compared with the unvaccinated group, the vaccinated group had a significantly higher positive rate of IgG on admission and at week 2 of the course of disease (P<0.05), as well as a significantly higher Ct value of nucleic acid at weeks 1 and 2 of the course of disease (P<0.05).@*CONCLUSIONS@#Vaccination with inactivated SARS-CoV-2 vaccine may reduce myocardial injury caused by SARS-CoV-2 Delta variant. For children with SARS-CoV-2 Delta variant infection after the vaccination, more attention should be paid to their immune function.

SARS-CoV-2 with transcription regulatory sequence motif mutation poses a greater threat / 南方医科大学学报

OBJECTIVE@#To analyze the mutations in transcription regulatory sequences (TRSs) of coronaviruss (CoV) to provide the basis for exploring the patterns of SARS-CoV-2 transmission and outbreak.@*METHODS@#A combined evolutionary and molecular functional analysis of all sets of publicly available genomic data of viruses was performed.@*RESULTS@#A leader transcription regulatory sequence (TRS-L) usually comprises the first 60-70 nts of the 5' UTR in a CoV genome, and the body transcription regulatory sequences (TRS-Bs) are located immediately upstream of the genes other than ORF1a and 1b. In each CoV genome, the TRS-L and TRS-Bs share a specific consensus sequence, namely the TRS motif. Any changes of nucleotide residues in the TRS motifs are defined as TRS motif mutations. Mutations in the TRS-L or multiple TRS-Bs result in superattenuated variants. The spread of super-attenuated variants may cause an increase in asymptomatic or mild infections, prolonged incubation periods and a decreased detection rate of the viruses, thus posing new challenges to SARS-CoV-2 prevention and control. The super-attenuated variants also increase their possibility of long-term coexistence with humans. The Delta variant is significantly different from all the previous variants and may lead to a large-scale transmission. The Delta variant (B.1.617.2) with TRS motif mutation has already appeared and shown signs of spreading in Singapore, which, and even the Southeast Asia, may become the new epicenter of the next wave of SARS-CoV-2 outbreak.@*CONCLUSION@#TRS motif mutation will occur in all variants of SARS-CoV-2 and may result in super-attenuated variants. Only super-attenuated variants with TRS motif mutations will eventually lose the abilities of cross-species transmission and causing outbreaks.

Epidemiological investigation of a case with SARS-CoV-2 infection associated with overseas countries at an international harbor / 预防医学

Objective@#To investigate the origin of infection and risk factors of a case with SARS-CoV-2 infection associated with overseas countries in the Ningbo-Zhoushan Port, Zhejiang Province, so as to provide the evidence for improving the COVID-19 control measures at ports.@*Methods@#Ningbo Center for Disease Control and Prevention ( CDC ) and Beilun CDC conducted case finding and epidemiological surveys immediately after being informed. The general information, history of vaccination and the travel during the latest 14 days were collected from the positive case, and all close contacts were tracked. Saliva samples were collected for SARS-CoV-2 nucleic acid testing and whole-genome sequencing, and the sequencing results were aligned with the GISAID's EpiCoV database. The origin of infection and transmission route of the positive case was investigated.@*Results@#A case was identified positive for SARS-CoV-2 nucleic acid during company M's routine screening in the Ningbo-Zhoushan Port on August 10, 2021, and was confirmed positive for SARS-CoV-2 nucleic acid by Beilun CDC and Ningbo CDC on August 11. Whole-genome sequencing showed SARS-CoV-2 B.1.617.2 ( Delta ) variant, which shared the highest homology with the virus sequence uploaded by Russia on June, 2021 ( Russia/MOW-RII-MH27356S/2021 ). The case was a bundling worker for overseas container ships, and reported communicated with foreign boatmen and contacted materials without protected interventions on the SINOKOR AKITA Container Ship between August 4 and 5, 2021. This ship anchored at Vladivostok, Russia from July 27 to 29, anchored at Ningbo Harbor on August 4, and departed on August 5. Then, 11 boatmen from this ship were tested positive for SARS-CoV-2 nucleic acid on August 8. One asymptomatic case was reported in this epidemic; 254 close contacts and 617 secondary close contacts were identified, and all were tested negative for SARS-CoV-2 nucleic acid. No new cases with SARS-CoV-2 infections were detected until August 25, 2021, and the emergency response was therefore terminated.@*Conclusions@#The infection was a sporadic COVID-19 epidemic associated with overseas countries, which was caused by Delta variant infection through contacts with foreign boatmen or materials by a bundling worker in Ningbo-Zhoushan Port; fortunately, no epidemic spread occurred. Intensified closed-loop management and increased frequency of SARS-CoV-2 nucleic acid test among high-risk populations, and improving the precision and rapid emergency treatment of COVID-19 epidemics are required for the containment of COVID-19 at ports.

Simulación de escenarios para predecir el comportamiento de la COVID-19 en Perú / Scenario simulation to predict the behavior of COVID-19 in Peru

Introducción: La COVID-19 ha constituido un reto de múltiples dimensiones para la humanidad, aún más para los decisores responsables de accionar de manera certera y oportuna para su enfrentamiento. En Perú, con una tendencia actual favorable de la Pandemia, es inminente la propagación de la variante Delta, de allí que requieran de informaciones predictivas que posibiliten adoptar decisiones anticipadas para mitigar sus efectos. Objetivo: Simular escenarios aplicando la modelación físico-matemática, para la predicción del comportamiento de la COVID-19 en Perú que facilite la adopción de decisiones. Material y Métodos: Modelación físico-matemática mediante herramientas y funciones del software MATLAB. Resultados: Determinación del comportamiento de las principales variables de la COVID-19 en Perú; modelo físico-matemático basado en el clásico SIR con nuevos compartimientos relacionados con la vacunación y los expuestos, así como su ajuste a los datos de Perú; simulación de escenarios, incluyendo la variante Delta, para fallecidos, infectados acumulados, infectados no vacunados e infectados vacunados. Conclusiones: El modelo concebido para la simulación de escenarios de evolución de la COVID-19, demostró su capacidad de predicción del comportamiento de las variables más importantes que determinan dicha evolución en Perú; debe ocurrir otra ola de contagios y llegarse a cifras acumulativas entre 2,9 y 3,36 millones de infectados y entre 215 y 255 mil fallecidos; las principales estrategias de mitigación deben dirigirse a garantizar el distanciamiento y aislamiento social, así como a incrementar el régimen de vacunación(AU)

Introduction: COVID-19 has been a multi-dimensional challenge for humanity, even more so for decision-makers responsible for acting in an accurate and timely manner to confront it. In Peru, with is a current favorable trend of the Pandemic, the spread of the Delta variant is imminent, hence the need for predictive information that makes it possible to make early decisions to mitigate its effects. Objective: To simulate scenarios applying the physical-mathematical modeling to predict the behavior of COVID-19 in Peru and facilitate decision-making. Material and Methods: Physical-mathematical modeling using MATLAB software tools and functions. Results: Determination of the behavior of the main variables associated with COVID-19 in Peru; physical-mathematical modeling based on the classic SIR with new compartments related to vaccination and those exposed, as well as its adjustment to the data from Peru; simulation of scenarios including the Delta variant for deceased persons, cumulative number of infected individuals, and infection in vaccinated and unvaccinated individuals. Conclusions: The model conceived for the simulation of COVID-19 evolution scenarios demonstrated its ability to predict the behavior of the most important variables that determine such evolution in Peru; another wave of infections may occur and cumulative figures between 2.9 and 3.36 million infected individuals and between 215 and 255 thousand deaths may be reached. The main mitigation strategies should be aimed at guaranteeing social distancing and isolation, as well as increasing the vaccination regimen(AU)

Emergencia de variante Delta- B. 1.617.2: su impacto potencial en la evolución de la pandemia por SARS-CoV-2 / Delta-B. 1.617.2 variant emergency:: its potential impact on the evolution of the SARS-CoV-2 pandemic

Se describe hasta la fecha de hoy, 4 de julio del 2021, la evidencia existente sobre la variante Delta del SARS-CoV-2, su impacto en la trasmisión, en la severidad de la infección y su probable evasión a la respuesta inmune. (AU)

As of today, July 4, 2021, the existing evidence on the Delta variant of SARS-CoV-2, its impact on transmission, on the severity of the infection and its probable evasion of the immune response is described. (AU)

Epidemic Characteristics of the Novel Coronavirus Delta Variant in Guangzhou and Grid Crowd Management Based on Public Security Forensic Perspective / 法医学杂志

Abstract： Objective To analyze the first epidemic spread of the novel coronavirus Delta variant in China based on public security forensic perspective, investigate its transmission characteristics, contributing factors, and epidemiologic research experience, and provide a reference for the prevention and control of the epidemic caused by the novel coronavirus variant. Methods Based on the information that public security forensic experts obtained from front-line epidemiologic research, the gender, age, place of residence, transmission route and infectivity of the coronavirus disease 2019 （COVID-19） confirmed cases, asymptomatic infected persons and their close contacts in Guangzhou caused by the novel coronavirus Delta variant were analyzed. The basic reproduction number （R0） during this epidemic in Guangzhou was calculated. Results Among the 153 cases infected with novel coronavirus Delta variant in the epidemic, 63 cases were male and 90 cases were female, their age ranging from 1 to 92 years, with a median age of 49 years. The main route of transmission was close contact, including dining together, co-living, and close contact in the same residential building. There were 31 cases of family clusters, 25 of which were in Liwan District. The epidemic lasted from May 26 to May 29, and the R0 remained above 4.0. After May 30, R0 began to decline and remained below 1.0 from June 7. Conclusion The novel coronavirus Delta variant is highly infectious, the crowd is generally susceptible to infection and family cluster cases are easy to occur. So, it is necessary to precisely prevent and control this strain. Public security forensic experts have both medical literacy and criminal investigation capabilities, they can play a more professional role in epidemic prevention and control.

Characteristics and control measures of 2019 novel coronavirus Delta variant of concern / 中华危重病急救医学

2019 novel coronavirus (2019-nCoV) Delta variant of concern (VOC) is one of the variants of 2019-nCoV, which has the characteristics of strong transmission, high pathogenicity, and rapid progression. 2019-nCoV Delta VOC has caused a global pandemic. Understanding the characteristics of 2019-nCoV Delta VOC and implementing targeted control measures are important aspects of controlling the pandemic. In this paper, the characteristics and control measures of 2019-nCoV Delta VOC were reviewed.

Clinical characteristics of coronavirus disease 2019 infected with Delta variant in Guangzhou:A real-world study / 中华急诊医学杂志

Objective:To summarize the clinical characteristics of patients with coronavirus disease 2019 (COVID-19) infected with Delta variant, so as to provide further references for clinical diagnosis and treatment.Methods:A real-world study was conducted to analyze the characteristics of 166 COVID-19 patients infected with Delta variant at Guangzhou Eighth People’s Hospital, Guangzhou Medical University.Results:The study enrolled 5 asymptomatic cases, 123 non-severe cases (mild and moderate type), and 38 severe cases (severe and critical type). Among these patients, 69 (41.6%) were male and 97 (58.4%) were female, with a mean age of 47.0±23.5 years. Thirty-nine cases (23.5%) had received 1 or 2 doses of inactivated vaccine. The incidence of severe COVID-19 cases was 7.7% in 2-doses vaccinated patients, which was lower than that of 11.5% in 1-dose and 26.8% in unvaccinated patients. The proportion of severe cases in 2 dose-vaccinated patients was 7.7%, which was lower than that of 11.5% in 1-dose vaccinated patients and 26.8% in unvaccinated patients, but the difference was not significant ( P>0.05). The most common clinical symptom was fever (134 cases, 83.2%), and 39.1% of cases presented with high-grade fever (≥39 °C); other symptoms were cough, sputum, fatigue, and xerostomia. The proportion of fever in severe cases was significantly higher than that of non-severe cases (97.4% vs. 76.4%, P<0.01). Similarly, the proportion of severe cases with high peak temperature (≥39 ℃) () was also higher than that of non-severe cases (65.8% vs. 30.9%, P<0.01). The median minimal Cycle threshold (Ct) values of viral nucleic acid N gene and ORFlab gene were 20.3 and 21.5, respectively, and the minimum Ct values were 11.9 and 13.5, respectively. Within 48 h of admission, 9.0% of cases presented with decreased white blood cell counts, and 52.4% with decreased lymphocyte counts. The proportions of increased C-reactive protein, serum amyloid A, interleukin 6, and interleukin 10 were 32.5%, 57.4%, 65.3%, and 35.7%, respectively. The proportions of elevated C-reactive protein, serum amyloid A and interleukin-6 in severe cases were significantly higher than those in non-severe cases ( P<0.01). Logistic regression analysis showed that older age and higher peak temperature were associated with a higher likelihood of severe cases ( OR>3, 95% CI: 2-7, P<0.01). In terms of treatment, traditional Chinese medicine (TCM) was used in 97.6% of non-severe cases and 100% in severe cases. Other treatments included respiratory and nutritional support, immunotherapy (such as neutralizing antibodies and plasma of recovered patients). The median times from admission to progression to severe cases, of fever clearance, and of nucleic acid conversion were 5 days, 6 days and 19 days, respectively. No deaths were reported within 28 days. Conclusions:The symptoms of Delta variant infection in Guangzhou are characterized by a high proportion of fever, high peak temperature, long duration of fever, high viral load, a long time to nucleic acid conversion, and a high incidence of severe cases. The severe cases exhibit a higher percentage of elderly patients, a longer duration of fever and have a higher fever rate and a higher hyperthermia rate than non-severe cases. Age and hyperthermia are independent risk factors for progression to severe disease. The combination of TCM and Western medicine can control the progression of the disease effectively.

Clinical features of children with coronavirus disease 2019 caused by Delta variant infection / 中国当代儿科杂志

OBJECTIVES@#To study the epidemiological and clinical features of children with coronavirus disease 2019 (COVID-19) caused by Delta variant infection and their differences from children with ordinary COVID-19 (non-Delta variant infection).@*METHODS@#Eleven children aged <14 years, who were diagnosed with COVID-19 caused by Delta variant infection from August to September 2021 were enrolled (variant group). Five children aged <14 years who were diagnosed with ordinary COVID-19 from February to March 2020 served as the control group. The epidemiological data, clinical features, and laboratory examination results were compared between the two groups.@*RESULTS@#There was no significant difference in the proportion of children with clinical symptoms between the two groups (@*CONCLUSIONS@#Delta variant is more infectious. COVID-19 caused by Delta variant infection may cause more serious myocardial damage than ordinary COVID-19 in children. In children infected with Delta variant, IgG antibody appears at almost the same time as IgM antibody.