[Survey on infection source of a cold-chain product associated COVID-19 epidemic caused by 2019-nCoV Delta variant in Beijing].

Objective: To investigate the source and the transmission chain of a cold-chain product associated COVID-19 epidemic caused by 2019-nCoV Delta variant in Beijing. Methods: Epidemiological investigation were used to verify the exposure points of the cases. Close contacts were traced from the exposure points, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: A total of 112 cases of COVID-19 were reported in the epidemic from January 18 to February 6, 2022 in Beijing. Except for 1 case was uncertain, there were epidemiological links among 111 cases. The source of infection was the packages of imported cold-chain products from Southeast Asia, which were harvested and stored in a local cold-storage in January 2021, and packaged and sent to the cold-storage A in A district in June 2021, and then sold in batches in cold-storage B in B district from January 2022. The first case was infected in the handling of positive frozen products, and then 77 cases occurred due to working, eating and living together with the index case in the cold-storage B, cold-storage C and restaurant D. Besides the cold-storage B, C and the restaurant D, there were 16 sub-transmission chains, resulting in additional 35 cases. Conclusion: The epidemic indicated that the risk of 2019-nCoV infection from imported cold-chain products contaminated by package and highlighted the importance to strengthen the management of cold-chain industry in future.

[Survey of possible aerosol transmission of a COVID-19 epidemic caused by 2019-nCoV Delta variant].

Objective: To investigate the epidemiological characteristics and the transmission chain of a family clustering of COVID-19 cases caused by severe acute respiratory 2019-nCoV Delta variant in Changping district of Beijing. Methods: Epidemiological investigation was conducted and big data were used to reveal the exposure history of the cases. Close contacts were screened according to the investigation results, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: On November 1, 2021, a total of 5 COVID-19 cases caused by 2019-nCoV Delta variant were reported in a family detected through active screening. The infection source was a person in the same designated isolation hotel where the first case of the family cluster was isolated from 22 to 27, October. The first case was possibly infected through aerosol particles in the ventilation duct system of the isolation hotel. After the isolation discharge on October 27, and the first case caused secondary infections of four family members while living together from October 27 to November 1, 2021. Conclusion: 2019-nCoV Delta variant is prone to cause family cluster, and close attention needs to be paid to virus transmission through ventilation duct system in isolation hotels.

[Survey on source of infection of the first local outbreak caused by SARS-CoV-2 Alpha variant in China].

Objective: To investigate the epidemiological characteristics and the chain of infection of a local outbreak, which was the first outbreak caused by severe acute respiratory syndrome corona virus 2 Alpha variant in China and occurred in Daxing district, Beijing. Methods: Epidemiological investigation and big data technology were used to verify the exposure points of the cases. Close contacts were traced from the exposure points, and their human and environmental samples were collected for nucleic acid tests. Serum samples were collected from key persons for antibody detection. Results: A total of 33 corona virus disease 2019(COVID-19) cases were reported in the local outbreak, from January 17, 2021 to January 29, 2021 in Daxing district, Beijing, and there was epidemiological association in 32 cases. Except for one case who was infected in the workplace, other cases were all infected in the community and family. All cases involved 14 families, of which 6 families were all infected. The attack rate of all family members was 69%(33/48), and the secondary attack rate was 56%(19/34). There was no obvious source of infection found after the investigation of entry-exit personnel and goods. Conclusion: The first outbreak caused by severe acute respiratory syndrome corona virus 2 Alpha variant in China is found and handled in time, and thus the scope of influence is limited, but the family clustering characteristics are more obvious than previous outbreaks.

[Relationship between respiratory viral load of cases of COVID-19 and secondary attack risk in close contacts].

Objective: To analyze the relationship between the cycle threshold (Ct) values of N gene of COVID-19 cases and the secondary attack risk in close contacts, and identify the relationship between respiratory viral load and infectivity in COVID-19 cases. Methods: The COVID-19 cases with records of Ct values of N gene within 0-7 days of onset were selected, and their close contacts were recruited as the subjects of study. We collected the information of close contacts, including name, gender, age, isolation mode, exposure mode and outcome (whether they were infected with SARS-CoV-2 or not) and other variables. Multivariate logistic regression models were used to identify the relationship between Ct values of N gene of COVID-19 cases and secondary attack risk in close contacts. Results: A total of 1 618 close contacts were recruited, in whom 77 were confirmed as symptomatic or asymptomatic COVID-19 patients with overall secondary attack rate of 4.8%. The multivariate logistic regression analysis indicated that eating together (OR=2.741, P=0.054), living together (OR=9.721, P<0.001), non-centralized isolation (OR=18.437, P<0.001) and COVID-19 case's values of N gene within 0-7 days of onset being <20 (OR=8.998, P=0.004) or 20-25 (OR=3.547, P=0.032) were significantly associated with higher likelihood of being infected with SARS-CoV-2 in close contacts. Conclusion: The results indicated that positive relationship exists between respiratory viral load and infectivity in COVID-19 cases, suggesting that Ct values of N gene can be used as an early warning indicator for the management of close contacts of COVID-19 cases.

[Application of the moving epidemic method in the development of epidemic thresholds and tiered warning alert approachs for influenza prevention in Beijing].

Objective: To calculate both the epidemic and intensity thresholds for different levels in Beijing and to establish a tiered alert system in the 2018-2019 influenza season as well as to evaluate the performance of calculated thresholds. Method: Weekly count of influenza-like illness and percentage of influenza-like illness (ILI%) of the last five influenza seasons were modeled by 'moving epidemic method' (MEM) to calculate the influenza epidemic and intensity thresholds at different levels. A cross-validation procedure was used to evaluate the performance. Indicators of Matthew correlation coefficient, Youden's index, sensitivity and specificity were calculated. Results: For weekly count of influenza-like illness, data showed that the epidemic threshold for 2018-2019 influenza season was 12 984 and the medium, high and very high intensity thresholds were 22 503, 37 589, 47 157, respectively. Matthew correlation coefficient of the epidemic threshold was 62% and youden's index as 60% , sensitivity as 69%, specificity as 91%. Data on weekly ILI%, the epidemic threshold for 2018-2019 influenza season was 1.66%, with medium, high and very high intensity thresholds as 2.46%, 3.84% and 4.66%, respectively. The overall Matthew correlation coefficient of the epidemic threshold was 59%, with 54% for the Youden's index, sensitivity as 60% and specificity as 94%. Conclusions: MEM produced a good specific signal for detecting the influenza epidemics and the accuracy of the method was acceptable. The early warning performance regarding the application of weekly count on influenza-like illness was slightly better than ILI%. This method could be applied in the practical influenza epidemic alert "work in Beijing" .

[Study on the super-antigen genes of group A Streptococcus pyogenes strains isolated from patients with scarlet fever and pharyngeal infection, in Beijing, 2015-2017].

Objective: To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS), isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. Methods: Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS. Eleven currently known SAg genes including SpeA, speC, speG, speH, speI, speJ, speK, speL, speM, smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR. Results: A total of 377 GAS were isolated from 6 801 throat swab specimens, with the positive rate as 5.5%. There were obvious changes noticed among speC, speG, speH and speK in three years. A total of 45 SAg genes profiles were observed, according to the SAgs inclusion. There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emm1 and emm12 strains (χ(2)=38.196, P<0.001; χ(2)=72.310, P<0.001). There also appeared significant differences in the frequencies of speA, speH, speI and speJ between emm1 and emm12 strains (χ(2)=146.154, P<0.001; χ(2)=52.31, P<0.001; χ(2)=58.43, P<0.001; χ(2)=144.70, P<0.001). Conclusions: Obvious changes were noticed among SAg genes including speC, speG, speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. SAg genes including speA, speH, speI and speJ appeared to be associated with the emm 1 and emm 12 strains. More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles, during the epidemic period.

[Characteristics on the onset features of scarlet fever in Beijing, 2006-2015].

Objective: This study aimed to explore the incidence trends and onset features of scarlet fever during the years of epidemic, from 2006 to 2015, in Beijing. Methods: Spatial, temporal and population distributions, prognosis of the reported cases and surveillance data on scarlet fever and other streptococcal infections (including the patients of streptococcal infection, tonsillitis and isthmitis) were analyzed by the descriptive epidemiological methods. Results: A total of 27 987 scarlet fever cases were reported from 2006 to 2015, with the incidence rates as 7.04 to 18.53 per 100 000 persons during these years, except for 2011. A total of 6 152 cases were reported in 2011, with the incidence of 31.37 per 100 000 persons, significantly higher than the average levels of the other years. There were more cases reported in rural-urban continuum, in summer and winter, with most of the cases were children in primary schools and infant-institutes. From May to December in 2011, 4 332 cases were interviewed three weeks after the disease onset, and their conditions improved or recovered, with no death or complication appeared at the follow-up period. There were 2 725 cases of scarlet fever and 104 013 clinical cases of streptococcal infections reported in 36 surveillance hospitals during the same period. The ratio between numbers of scarlet fever cases and streptococcal infection was 1 ∶ 38.17. The weekly numbers of scarlet fever were remarkably correlated to the streptococcal infections, with a Pearson's correlation coefficient as 0.729 (P<0.001). Accordingly, we estimated that about 21.4 thousand clinical cases of streptococcal infections that were caused by Group A streptococcus in 2011, in Beijing. Conclusions: Incidence of scarlet fever in 2011 was significantly higher than the average levels of other years in Beijing, but characteristics on spatial, temporal and population distributions of scarlet fever remained the same, with good prognosis of the reported cases. A large number of culture-positive Group A streptococcus infections among all the clinical cases of streptococcal infection might have been served as important source on septic infection, of scarlet fever.

Examining the effect of gene reduction in miR-95 and enhanced radiosensitivity in non-small cell lung cancer.

MicroRNAs (miRNAs) represent a group of novel therapeutic small molecules involved in the management of lung cancer treatment. Our study aims to investigate the potential role of miRNAs in the treatment of non-small cell lung cancer (NSCLC). Human miRNA microarray was performed in 60 recurrent NSCLC patient tissue samples following radiotherapy and their adjacent normal tissues. miRNA profiling results were validated using quantitative real-time PCR. Inner cell radiosensitivity and endogenous miRNA expression was determined by colony-formation assay and RT-PCR. We determined the effect of miRNA on cell proliferation, survival and metastasis; tumor xenografts were taken to identify the presence of miRNA in vivo. miRNA panel results indicated that a total of 14 miRNAs were differentially expressed in the recurrent NSCLC samples. In our study, miRNA-95 was highly overexpressed in recurrent NSCLC cells. Knockdown of miRNA-95 expression increased the radiosensitivity of NSCLC, promoted tumor cell apoptosis and decreased cellular proliferation. In vivo assays demonstrated reduced tumor growth and resistance to radiation in tumor xenografts by downregulating miRNA-95. Our study demonstrated a potential therapeutic measure of miRNA-95 as a radiosensitive marker for the treatment of non-small lung cancer.

Role of VEGF gene polymorphisms in the clinical outcome of non-small cell lung cancer.

This report details a study conducted to assess the role of VEGF gene polymorphisms in the prognosis of advanced non-small cell lung carcinoma (NSCLC). Samples obtained from 210 advanced NSCLC patients admitted at the Huaihe Hospital of Henan University between January 2010 and December 2011 were recruited for this study. The VEGF -2578C/A (rs699947), +936C/T (rs3025039), and -634G/C (rs2010963) genotypes were analyzed by polymerase chain reaction-restriction fragment length polymorphism. We discovered, by logistic regression analysis, that the TT genotype of VEGF +936C/T was associated with more complete response + partial response to chemotherapy, compared to the CC genotype (odds ratio (OR) = 4.78, 95% confidence interval (CI) = 1.34-25.85). We also found a correlation between the TT genotype of VEGF +936C/T and lower risk of death from all causes compared to the CC genotype (OR = 0.26, 95%CI = 0.10-0.69), using the Cox proportional hazard model (after adjusting for potential confounding factors). In conclusion, we discovered that the VEGF +936C/T gene polymorphism influences the response to chemotherapy and overall survival of NSCLC patients.