scholarly journals Transmission and containment of the SARS-CoV-2 Delta variant of concern in Guangzhou, China: A population-based study

2022 ◽  
Vol 16 (1) ◽  
pp. e0010048
Author(s):  
Li Li ◽  
Zhi-Gang Han ◽  
Peng-Zhe Qin ◽  
Wen-Hui Liu ◽  
Zhou Yang ◽  
...  

Background The first community transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant of concern (VOC) in Guangzhou, China occurred between May and June 2021. Herein, we describe the epidemiological characteristics of this outbreak and evaluate the implemented containment measures against this outbreak. Methodology/Principal findings Guangzhou Center for Disease Control and Prevention provided the data on SARS-CoV-2 infections reported between 21 May and 24 June 2021. We estimated the incubation period distribution by fitting a gamma distribution to the data, while the serial interval distribution was estimated by fitting a normal distribution. The instantaneous effective reproductive number (Rt) was estimated to reflect the transmissibility of SARS-CoV-2. Clinical severity was compared for cases with different vaccination statuses using an ordinal regression model after controlling for age. Of the reported local cases, 7/153 (4.6%) were asymptomatic. The median incubation period was 6.02 (95% confidence interval [CI]: 5.42–6.71) days and the means of serial intervals decreased from 5.19 (95% CI: 4.29–6.11) to 3.78 (95% CI: 2.74–4.81) days. The incubation period increased with age (P<0.001). A hierarchical prevention and control strategy against COVID-19 was implemented in Guangzhou, with Rt decreasing from 6.83 (95% credible interval [CrI]: 3.98–10.44) for the 7-day time window ending on 27 May 2021 to below 1 for the time window ending on 8 June and thereafter. Individuals with partial or full vaccination schedules with BBIBP-CorV or CoronaVac accounted for 15.3% of the COVID-19 cases. Clinical symptoms were milder in partially or fully vaccinated cases than in unvaccinated cases (odds ratio [OR] = 0.26 [95% CI: 0.07–0.94]). Conclusions/Significance The hierarchical prevention and control strategy against COVID-19 in Guangzhou was timely and effective. Authorised inactivated vaccines are likely to contribute to reducing the probability of developing severe disease. Our findings have important implications for the containment of COVID-19.

2020 ◽  
Author(s):  
Suling Mao ◽  
Ting Huang ◽  
Heng Yuan ◽  
Min Li ◽  
Xiaomei Huang ◽  
...  

Abstract Background This study was intended to investigate the epidemiological characteristics of COVID-19 clusters and the severity distribution of clinical symptoms of involved cases in Sichuan Province, so as to provide information support for the development and adjustment of strategies for the prevention and control of local clusters.Methods The epidemiological characteristics of 67 local clusters of COVID-19 cases in Sichuan Province reported as of March 17, 2020 were described and analyzed. Information about all COVID-19 clusters and involved cases was acquired from the China Information System for Disease Control and Prevention and analyzed with the epidemiological investigation results taken into account.Results The clusters were temporally and regionally concentrated. Clusters caused by imported cases from Wuhan and other provinces except Wuhan accounted for 73.13%; familial clusters accounted for 68.66%; the average attack rate was 8.54%, and the average secondary attack rate was 6.11%; the median incubation period was 8.5 d;a total of 28 cases met the criteria for incubation period determination, and in the 28 cases, the incubation period was > 14 d in 21.43% (6/28). a total of 226 confirmed cases were reported in the 67 clusters. Ten cases were exposed before the confirmed cases they contacted with developed clinical symptoms, and the possibility of exposure to other infection sources was ruled out; two clusters were caused by asymptomatic carriers; confirmed cases mainly presented with fever, respiratory and systemic symptoms; a gradual decline in the severity of clinical symptoms was noted with the increase of the case generation.Conclusions Population movement and gathering restrictions and strict close contact management measures will significantly contribute to the identification and control of cases. Transmission during the incubation period and asymptomatic infections have been noted. Studies on the pathogenicity and transmissibility in these populations and on COVID-19 antibody levels and protective effects in healthy people and cases are required.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Suling Mao ◽  
Ting Huang ◽  
Heng Yuan ◽  
Min Li ◽  
Xiaomei Huang ◽  
...  

Abstract Background This study was intended to investigate the epidemiological characteristics of COVID-19 clusters and the severity distribution of clinical symptoms of involved cases in Sichuan Province, so as to provide information support for the development and adjustment of strategies for the prevention and control of local clusters. Methods The epidemiological characteristics of 67 local clusters of COVID-19 cases in Sichuan Province reported as of March 17, 2020 were described and analyzed. Information about all COVID-19 clusters and involved cases was acquired from the China Information System for Disease Control and Prevention and analyzed with the epidemiological investigation results taken into account. Results The clusters were temporally and regionally concentrated. Clusters caused by imported cases from other provinces accounted for 73.13%; familial clusters accounted for 68.66%; the average attack rate was 8.54%, and the average secondary attack rate was 6.11%; the median incubation period was 8.5 d; a total of 28 cases met the criteria for incubation period determination, and in the 28 cases, the incubation period was > 14 d in 21.43% (6/28). a total of 226 confirmed cases were reported in the 67 clusters. Ten cases were exposed before the confirmed cases they contacted with developed clinical symptoms, and the possibility of exposure to other infection sources was ruled out; two clusters were caused by asymptomatic carriers; confirmed cases mainly presented with fever, respiratory and systemic symptoms; a gradual decline in the severity of clinical symptoms was noted with the increase of the case generation. Conclusions Population movement and gathering restrictions and strict close contact management measures will significantly contribute to the identification and control of cases. Transmission during the incubation period and asymptomatic infections have been noted. Studies on the pathogenicity and transmissibility in these populations and on COVID-19 antibody levels and protective effects in healthy people and cases are required.


2020 ◽  
Author(s):  
Qiangsheng Huang

BACKGROUND As of the end of February 2020, 2019-nCoV is currently well controlled in China. However, the virus is now spreading globally. OBJECTIVE This study aimed to evaluate the effectiveness of outbreak prevention and control measures in a region. METHODS A model is built for find the best fit for two sets of data (the number of daily new diagnosed, and the risk value of incoming immigration population). The parameters (offset and time window) in the model can be used as the evaluation of effectiveness of outbreak prevention and control. RESULTS Through study, it is found that the parameter offset and time window in the model can accurately reflect the prevention effectiveness. Some related data and public news confirm this result. And this method has advantages over the method using R0 in two aspects. CONCLUSIONS If the epidemic situation is well controlled, the virus is not terrible. Now the daily new diagnosed patients in most regions of China is quickly reduced to zero or close to zero. Chinese can do a good job in the face of huge epidemic pressure. Therefore, if other countries can do well in prevention and control, the epidemic in those places can also pass quickly.


2011 ◽  
Vol 16 (41) ◽  
Author(s):  
C C Wielders ◽  
R S van Binnendijk ◽  
B E Snijders ◽  
G A Tipples ◽  
J Cremer ◽  
...  

We assessed the epidemiological characteristics of a mumps virus epidemic (genotype D) that occurred in the Netherlands between August 2007 and May 2009 and its association with a subsequent mumps outbreak in Canada. In the Netherlands, five data sources were used: notifications (only mandatory since the end of 2008) (56 cases), laboratory confirmation data (177 cases), a sentinel general practitioner (GP) database (275 cases), hospitalisation data (29 cases) and weekly virological reports (96 cases). The median age of cases in the notification, laboratory and GP databases ranged from 13 to 15 years. The proportion of cases that were unvaccinated ranged from 65% to 85% in the notification, laboratory and GP databases. Having orthodox Protestant beliefs was the main reason for not being vaccinated. In Canada, a mumps virus strain indistinguishable from the Dutch epidemic strain was detected between February and October 2008 in an orthodox Protestant community with historical and family links to the affected community in the Netherlands, suggesting that spread to Canada had occurred. Prevention and control of vaccine-preventable diseases among population subgroups with low vaccination coverage remains a priority.


2021 ◽  
Vol 25 (5) ◽  
pp. 373-381
Author(s):  
L. Ferreiro ◽  
A. Ruano-Raviña ◽  
R. Otero-Mallo ◽  
C. Pou-Álvarez ◽  
V. Riveiro-Blanco ◽  
...  

OBJECTIVE: To describe the epidemiological trends and characteristics of extrapulmonary tuberculosis (EPTB) in Galicia, Spain, from 2000 to 2019.METHODS: This was a retrospective cohort study based on data from the Galician TB information system.RESULTS: Of the total number of TB cases (n = 15,871), 5,428 (34.2%) had EPTB. The absolute number of cases and incidence of EPTB decreased dramatically (from 480 cases and 17.8 cases/100,000 in 2000, to 172 and 6.4 cases/100,000 in 2019, respectively), with a mean annual decrease of respectively 64% and 4.7% for absolute cases and incidence rates. The risk for EPTB was higher in men than in women (RR 3.86, 95% CI 3.66–4.07). The most frequent age group was 15–44 years (2,234 patients, 41.2%); overall reductions per age group were 82% (0–14 years), 75% (15–44 years), 44% (45–64 years) and 63% (≥65 years), with statistically significant differences. The most frequently locations were the pleura (1,916 cases; 35.3%) and the lymph nodes (1,504; 27.7%).CONCLUSION: The incidence of EPTB in Galicia has decreased significantly in the last 20 years. The epidemiological characteristics have not changed, except for the number of patients with risk factors. This improvement of EPTB epidemiological trends coincides with the implementation of the programme for the prevention and control of TB, which suggests that it has been very effective in the control of the EPTB.


2020 ◽  
Vol 28 (5) ◽  
pp. 623-630
Author(s):  
Biao Cheng ◽  
Yufeng Jiang ◽  
Xiaobing Fu ◽  
Daifeng Hao ◽  
Hongwei Liu ◽  
...  

2020 ◽  
Vol 148 ◽  
Author(s):  
L. Z. Chen ◽  
Z. H. Lin ◽  
J. Chen ◽  
S. S. Liu ◽  
T. Shi ◽  
...  

Abstract ‘Recurrence’ of coronavirus disease 2019 (COVID-19) has triggered numerous discussions of scholars at home and abroad. A total of 44 recurrent cases of COVID-19 and 32 control cases admitted from 11 February to 29 March 2020 to Guanggu Campus of Tongji Hospital affiliated to Tongji Medical College Huazhong University of Science and Technology were enrolled in this study. All the 44 recurrent cases were classified as mild to moderate when the patients were admitted for the second time. The gender and mean age in both cases (recurrent and control) were similar. At least one concomitant disease was observed in 52.27% recurrent cases and 34.38% control cases. The most prevalent comorbidity among them was hypertension. Fever and cough being the most prevalent clinical symptoms in both cases. On comparing both the cases, recurrent cases had markedly elevated concentrations of alanine aminotransferase (ALT) (P = 0.020) and aspartate aminotransferase (AST) (P = 0.007). Moreover, subgroup analysis showed mild to moderate abnormal concentrations of ALT and AST in recurrent cases. The elevated concentrations of ALT and AST may be recognised as predictive markers for the risk of ‘recurrence’ of COVID-19, which may provide insights into the prevention and control of COVID-19 in the future.


2019 ◽  
Vol 115 ◽  
pp. 01001
Author(s):  
Zhen Hu ◽  
Ding Wang ◽  
Yangwu Shen ◽  
Daojun Chen ◽  
Yongyan Liu

The purpose of voltage stability prevention and control strategy is to minimize the impact of expected accidents on the whole power grid while ensuring safe power supply. In this paper, it is expected that the accident has a large impact on the system voltage and makes the voltage margin of each node low. in order to not only adjust the node voltage, but also reduce the disturbance impact, a voltage stability prevention and control strategy is proposed based on the characteristic analysis.


2018 ◽  
Vol 17 (1) ◽  
Author(s):  
Jonathan N. Hogarh ◽  
Thomas P. Agyekum ◽  
Crentsil Kofi Bempah ◽  
Emmanuel D. J. Owusu-Ansah ◽  
Silas W. Avicor ◽  
...  

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