scholarly journals Epidemiological analysis of 67 local COVID-19 clusters in Sichuan Province, China

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):  
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.


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.


2021 ◽  
Author(s):  
Abu Shadat M Noman ◽  
Mohammed Rezaul Karim ◽  
ASM Zahed ◽  
ATM Rezaul Karim ◽  
Syed S Islam

Abstract Background: Transmission risk of coronavirus disease 2019 (COVID-19) to close contacts and at different exposure settings are yet to be fully understood for the evaluation of effective control measures. Methods: We traced 1171 close contact cases who were linked to 291 index cases between July 3, 2020 and September 3, 2020. Clinical and epidemiological characteristics of all index cases, close contacts, and secondary contact cases were collected and analyzed the secondary attack rate and risk of transmission at different exposure settings. Results: Median age of 291 index cases were 43.0 years (range 18.5-82.3) including 213 male and 78 females. Among all 1171 close contact cases, 39(3.3%) cases were identified as secondary infected cases. Among 39 secondary cases, 33(84.62%) cases were symptomatic and 3 (7.69%) cases were asymptomatic. Of the 33 symptomatic cases, 31(86.1%) male and 5(13.9%) female. Of these 36 symptomatic cases, 24(66.7%) cases between age 20-59 and remaining 12(33.3%) cases were age 60 and over. Of the 36 symptomatic cases, 11(30.6%) cases were identified as severe, 19(52.8%) as moderate and 6(16.7%) as mild. The overall secondary clinical attack rate was 3.07% (95% CI 2.49-3.64). The attack rate was higher among those aged between 50 to 69 years and shows higher risk of transmission than age below 50 years. The attack rate was higher among household contact (6.17%(95%CI 4.7-7.6; risk ratio 2.44[95%CI1.5-3.4]), and lower in hospital facility (2.29%,95%CI0.58-3.40; [risk ratio 0.91,95%CI 0.17-1.9]), funeral ceremony (2.53%,95%CI 0.32-4.73), work places (3.95%,95% CI2.5-5.42 [risk ratio 1.56,95%CI 0.63-2.5]), family contacts (3.87%,95%CI 2.4-5.3; risk ratio 1.53,95%CI 0.61-2.45]). Conclusions: Among all exposure settings analyzed, household contact exposure setting remained the highest transmission probability and risk of transmission of COVID-19 with the increase of age and disease severity.


2020 ◽  
Vol 1 (1) ◽  
pp. 31-43
Author(s):  
Mohammad Reza Naghii

Identifying the epidemiological characteristics of COVID-19 disease will help to make appropriate decisions and thus control the epidemic. Although many details, such as the source of the virus and its ability to spread between people remain unknown, an increasing number of cases show the signs of human-to-human transmission. The purpose of this review is to introduce the reservoir hosts, and the possible role of distributions of bat coronaviruses in China, and eventually to aim to predict virus natural hotspots and their cross-species transmission potential. Why bats can maintain coronaviruses long-term without showing clinical symptoms of diseases and what is allowing bats to have a higher tolerance against viral diseases. We need to unveil the mystery of unique bat immunity. Although bats are not in close contact with humans, spillover of viruses from bats to intermediate animal hosts like civet is thought to be the most likely mode to cause human infection. It appears that the coffee beans which are a rich source of chlorogenic acid are acting as a reservoir host and causative agent, and at the same time as a defense agent to create resistance in the consumers (bats and animals). It is assumed that the intake of chlorogenic acid should be capable of protecting human from contamination or severe morbidity.


2020 ◽  
Author(s):  
Xinyin Xu ◽  
Jing Zeng ◽  
Runyou Liu ◽  
Yang Liu ◽  
Xiaobo Zhou ◽  
...  

Abstract Background: The COVID-19 spread worldwide quickly. Exploring the epidemiological characteristics could provide a basis for responding to imported cases abroad and to formulate prevention and control strategies in areas where COVID-19 is still spreading rapidly. Methods: The number of confirmed cases, daily growth, incidence and length of time from the first reported case to the end of the local cases (i.e., non-overseas imported cases) were compared by spatial (geographical) and temporal classification and visualization of the development and changes of the epidemic situation by layers through maps. Results: In the first wave, a total of 539 cases were reported in Sichuan, with an incidence rate of 0.6462/100,000. The closer to Hubei the population centres were, the more pronounced the epidemic was. The peak in Sichuan Province occurred in the second week. Eight weeks after the Wuhan lockdown, the health crisis had eased. The longest epidemic length at the city level in China (except Wuhan, Taiwan, and Hong Kong) was 53 days, with a median of 23 days. Spatial autocorrelation analysis of China showed positive spatial correlation (Moran's Index >0, p<0.05). Most countries outside China began to experience a rapid rise in infection rates 4 weeks after their first case. Some European countries experienced that rise earlier than the USA. The pandemic in Germany, Spain, Italy, and China took 28, 29, 34, and 18 days, respectively, to reach the peak of daily infections, after their daily increase of up to 20 cases. During this time, countries in the African region and Southeast Asian region were at an early stage of infections, those in the Eastern Mediterranean region and region of the Americas were in a rapid growth phase. Conclusions: After the closure of the outbreak city, appropriate isolation and control measures in the next 8 weeks were key to control the outbreak, which reduced the peak value and length of the outbreak. Some countries with improved epidemic situations need to develop a continuous "local strategy at entry checkpoints" to respond to a possible second local epidemic.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Xinyin Xu ◽  
Jing Zeng ◽  
Runyou Liu ◽  
Yang Liu ◽  
Xiaobo Zhou ◽  
...  

Abstract Background The COVID-19 spread worldwide quickly. Exploring the epidemiological characteristics could provide a basis for responding to imported cases abroad and to formulate prevention and control strategies in areas where COVID-19 is still spreading rapidly. Methods The number of confirmed cases, daily growth, incidence and length of time from the first reported case to the end of the local cases (i.e., non-overseas imported cases) were compared by spatial (geographical) and temporal classification and visualization of the development and changes of the epidemic situation by layers through maps. Results In the first wave, a total of 539 cases were reported in Sichuan, with an incidence rate of 0.6462/100,000. The closer to Hubei the population centres were, the more pronounced the epidemic was. The peak in Sichuan Province occurred in the second week. Eight weeks after the Wuhan lockdown, the health crisis had eased. The longest epidemic length at the city level in China (except Wuhan, Taiwan, and Hong Kong) was 53 days, with a median of 23 days. Spatial autocorrelation analysis of China showed positive spatial correlation (Moran’s Index > 0, p < 0.05). Most countries outside China began to experience a rapid rise in infection rates 4 weeks after their first case. Some European countries experienced that rise earlier than the USA. The pandemic in Germany, Spain, Italy, and China took 28, 29, 34, and 18 days, respectively, to reach the peak of daily infections, after their daily increase of up to 20 cases. During this time, countries in the African region and Southeast Asian region were at an early stage of infections, those in the Eastern Mediterranean region and region of the Americas were in a rapid growth phase. Conclusions After the closure of the outbreak city, appropriate isolation and control measures in the next 8 weeks were key to control the outbreak, which reduced the peak value and length of the outbreak. Some countries with improved epidemic situations need to develop a continuous “local strategy at entry checkpoints” to to fend off imported COVID-19.


2020 ◽  
Vol 42 (3) ◽  
pp. 656-658
Author(s):  
Hao Sang ◽  
Yan Cui ◽  
Xiaobin Lai ◽  
Yuyan Zhang ◽  
Lingna Kong ◽  
...  

Abstract An ongoing outbreak of coronavirus disease 2019 (COVID-19) has rapidly spread in the world, whereas asymptomatic carriers may also play a critical role in the pandemic. We report a familial cluster of COVID-19 caused by one family member before his onset of illness, indicating that it seems to be potentially infectious during the incubation period, even earlier than we expected. Close contact, especially in a small enclosed space, might be the cause of familial transmission. The unsynchronized changes in the clinical symptoms and COVID-19 nucleic acid were found in this case, so consecutive nucleic acid detection of pretty suspected cases was recommended. Family members, especially of whom the confirmed cases contacted with since one incubation period before onset rather than 2 days before onset, should be regarded as close contact and centrally isolated in case of asymptomatic infection already existed in the family.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9360 ◽  
Author(s):  
Chih-Ming Chang ◽  
Ting-Wan Tan ◽  
Tai-Cheng Ho ◽  
Chung-Chu Chen ◽  
Tsung-Hsien Su ◽  
...  

Background Coronavirus disease 19 (COVID-19) is a global health threat with significant medical, economic, social and political implications. The optimal strategies for combating COVID-19 have not been fully determined and vary across countries. Methods By the end of February 2020 in Taiwan, 2,150 patients received diagnostic COVID-19 testing and 39 confirmed cases were detected. This is a relatively lower rate of infection compared to other Asian countries. In this article, we summarize the epidemiological characteristics of the 39 infected patients as well as public and hospital responses to COVID-19. Results Thirty-nine COVID-19 cases and one death have been confirmed in Taiwan. Seventeen of these patients were infected by family members or in hospital wards, emphasizing how COVID-19 is mostly spread by close contact. We examined how hospital have responded to COVID-19, including their implementation of patient route control, outdoor clinics, hospital visit restrictions and ward and staff modifications. We also studied the public’s use of face masks in response to COVID-19. These strategies may reduce the spread of COVID-19 in other countries. Conclusion The emergence and spread of COVID-19 is a threat to health worldwide. Taiwan has reported lower infected cases and its strategies may contribute to further disease prevention and control.


2022 ◽  
Vol 8 ◽  
Author(s):  
Jing Ai ◽  
Yuanzhao Zhu ◽  
Jianguang Fu ◽  
Xiaoqing Cheng ◽  
Xuefeng Zhang ◽  
...  

Objective: To describe the epidemiological characteristics of norovirus outbreaks in Jiangsu Province, utilize the total attack rate (TAR) and transmissibility (Runc) as the measurement indicators of the outbreak, and a statistical difference in risk factors associated with TAR and transmissibility was compared. Ultimately, this study aimed to provide scientific suggestions to develop the most appropriate prevention and control measures.Method: We collected epidemiological data from investigation reports of all norovirus outbreaks in Jiangsu Province from 2012 to 2018 and performed epidemiological descriptions, sequenced the genes of the positive specimens collected that were eligible for sequencing, created a database and calculated the TAR, constructed SEIAR and SEIARW transmission dynamic models to calculate Runc, and performed statistical analyses of risk factors associated with the TAR and Runc.Results: We collected a total of 206 reported outbreaks, of which 145 could be used to calculate transmissibility. The mean TAR in was 2.6% and the mean Runc was 12.2. The epidemiological characteristics of norovirus outbreaks showed an overall increasing trend in the number of norovirus outbreaks from 2012 to 2018; more outbreaks in southern Jiangsu than northern Jiangsu; more outbreaks in urban areas than in rural areas; outbreaks occurred mostly in autumn and winter. Most of the sites where outbreaks occurred were schools, especially primary schools. Interpersonal transmission accounted for the majority. Analysis of the genotypes of noroviruses revealed that the major genotypes of the viruses changed every 3 years, with the GII.2 [P16] type of norovirus dominating from 2016 to 2018. Statistical analysis of TAR associated with risk factors found statistical differences in all risk factors, including time (year, month, season), location (geographic location, type of settlement, type of premises), population (total number of susceptible people at the outbreak site), transmission route, and genotype (P &lt; 0.05). Statistical analysis of transmissibility associated with risk factors revealed that only transmissibility was statistically different between sites.Conclusions: The number of norovirus outbreaks in Jiangsu Province continues to increase during the follow-up period. Our findings highlight the impact of different factors on norovirus outbreaks and identify the key points of prevention and control in Jiangsu Province.


2019 ◽  
Vol 29 (3) ◽  
pp. 235-242
Author(s):  
Vivi Setiawaty ◽  
Chita Septiawati ◽  
Endang Burni

Abstract Rabies is a zoonotic disease that is transmitted to humans by bites or scratches or licks (on damaged skin or mucous membranes) from infected animals, most often dogs. Rabies is endemic in several regions in Indonesia. If untreated, bites of rabies will cause fatal. The aim of this analysis is to explore the characteristics of fatal human cases caused by the bites of rabies transmitting animal in Indonesia in 2016–2017. The collection of human case data with bites of rabies transmitting animals (GHPR) from all provinces of Indonesia in 2016 and 2017 by the zoonotic Subdirectorate, Directorate Pencegahan dan Pengendalian Penyakit Tular Vektor dan Zoonosis (P2PTVZ), Directorat General of Disease Prevention and Control. We analyzed tha characteristics of the provincial which was reported GHPR cases, incubation period, bite location, clinical symptoms, history of vaccination and the demography of fatal GHPR cases. The clinical case definition for GHPR based on the World Health Organization. The results show that GHPR cases were reported from 25 out of 34 provinces. The most frequently reported incubation period is 1-2 month (40.7%). The location of most bites on the legs (37.3%). Most clinical symptoms reported were hydrophobia (76.6%), followed by hypersalivation (64.5%), convulsion (35.5%), photophobia and hyperhidrosis respectively (31.2%). Fever is not the main symptom, only 19.9%. Most fatal GHPR cases do not receive appropriate vaccination post-exposure (VAR). Male as fatal GHPR cases are more often than women with ratio 1.8 to 1 and adult cases more than children. Inconclusions immediate treatment with complete post-exposure vaccination has not been well implemented in reported fatal GHPR cases.  Abstrak Rabies merupakan salah satu penyakit zoonosis yang ditularkan ke manusia melalui gigitan atau goresan atau jilatan (pada kulit yang rusak atau selaput lendir) dari hewan yang terinfeksi, paling sering anjing. Rabies endemis di beberapa daerah di Indonesia. Jika tidak ditangani, gigitan hewan rabies dapat menyebabkan kematian. Tujuan dari penulisan ini untuk memberi informasi karakteristik kasus manusia yang fatal akibat gigitan hewan penular rabies (GHPR) di Indonesia selama kurun waktu 2016- 2017. Pengumpulan data kasus manusia dengan gigitan hewan penular rabies dari seluruh provinsi Indonesia pada tahun 2016 dan 2017 dilakukan oleh Subdirektorat Zoonosis, Direktorat Pencegahan dan Pengendalian Penyakit Tular Vektor dan Zoonosis (P2PTVZ), Direktorat Jenderal Pencegahan dan Pengendalian Penyakit (P2P). Analisis karakteristik kasus GHPR fatal meliputi aspek provinsi yang melaporkan kasus GHPR, masa inkubasi, lokasi gigitan, gejala klinis, riwayat pemberian vaksinasi dari kasus fatal dan demografi. Definisi kasus GHPR secara klinis berdasarkan Organisasi Kesehatan Dunia. Hasil menunjukkan bahwa kasus GHPR dilaporkan di 25 dari 34 provinsi. Masa inkubasi yang paling sering dilaporkan yaitu 1-2 bulan (40,7%). Lokasi gigitan terbanyak pada kaki (37,3%). Gejala klinis terbanyak yang dilaporkan hidrofobia (76,6%), diikuti dengan hipersalivasi (64,5%), kejang (35,5%), fotofobia dan hiperhidrosis masing-masing (31,2%). Demam bukan gejala utama, hanya 19,9%. Sebagian besar kasus GHPR fatal tidak mendapatkan vaksinasi pascapajanan (VAR) yang sesuai. Kasus GHPR fatal pada laki-laki lebih banyak daripada perempuan dengan perbandingan 1,8 : 1 dan jumlah orang dewasa lebih banyak dibandingkan dengan anak-anak. Disimpulkan bahwa pengobatan segera dengan pemberian vaksinasi pascapajanan secara lengkap belum dilaksanakan dengan baik pada kasus-kasus GHPR fatal yang dilaporkan.


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