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1.
Emerg Microbes Infect ; 10(1): 1751-1759, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34396940

RESUMO

The effectiveness of inactivated SARS-CoV-2 vaccines against the Delta variant, which has been associated with greater transmissibility and virulence, remains unclear. We conducted a test-negative case-control study to explore the vaccine effectiveness (VE) in real-world settings. We recruited participants aged 18-59 years who consisted of SARS-CoV-2 test-positive cases (n = 74) and test-negative controls (n = 292) during the outbreak of the Delta variant in May 2021 in Guangzhou city, China. Vaccination status was compared to estimate The VE of SARS-CoV-2 inactivated vaccines. A single dose of inactivated SARS-CoV-2 vaccine yielded the VE of only 13.8%. After adjusting for age and sex, the overall VE for two-dose vaccination was 59.0% (95% confidence interval: 16.0% to 81.6%) against coronavirus disease 2019 (COVID-19) and 70.2% (95% confidence interval: 29.6-89.3%) against moderate COVID-19 and 100% against severe COVID-19 which might be overestimated due to the small sample size. The VE of two-dose vaccination against COVID-19 reached 72.5% among participants aged 40-59 years, and was higher in females than in males against COVID-19 and moderate diseases. While single dose vaccination was not sufficiently protective, the two-dose dosing scheme of the inactivated vaccines was effective against the Delta variant infection in real-world settings, with the estimated efficacy exceeding the World Health Organization minimal threshold of 50%.


Assuntos
Vacinas contra COVID-19/normas , COVID-19/prevenção & controle , SARS-CoV-2/genética , Adolescente , Adulto , Distribuição por Idade , COVID-19/classificação , Vacinas contra COVID-19/administração & dosagem , Estudos de Casos e Controles , China , Surtos de Doenças , Feminino , Variação Genética , Humanos , Masculino , Pessoa de Meia-Idade , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/normas , Adulto Jovem
2.
Expert Rev Vaccines ; 20(7): 907-918, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34036862

RESUMO

Background: Since 2016, China has approved the use of inactivated enterovirus 71 (EV71) vaccines produced by three manufacturers. The coverage and safety of different EV71 vaccines need to be evaluated.Research design and methods: The EV71 vaccination and AEFI data were collected from the Guangzhou Children's Vaccination Information Report Management System and the China AEFI Monitoring Information Management System, and the EV71 vaccine coverage rate and the AEFI incidence rate were analyzed.Results: From 2016 to 2019, the number of people who should have been vaccinated in Guangzhou was 2,781,618, and the coverage rates for doses 1 and 2 were 24.71% and 19.44%, respectively. The inoculation rates of vaccines from manufacturers A and B were between 3.03 and 10.46%. The reported incidence of AEFIs was 11.97 per 100,000 (147 cases), with fever (106 cases, 8.63 per 100,000) and allergic rash (59 cases, 4.80 per 100,000) being the most common reactions. There were no differences in the AEFI responses to the EV71 vaccines from the three manufacturers.Conclusion: The EV71 vaccines from the three manufacturers have good safety, but the EV71 vaccine coverage rate is low. It is recommended that vaccine publicity be strengthened and that the vaccine coverage rate in children be increased.

3.
J Clin Microbiol ; 59(8): e0007921, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-33952598

RESUMO

While China experienced a peak and decline in coronavirus disease 2019 (COVID-19) cases at the start of 2020, regional outbreaks continuously emerged in subsequent months. Resurgences of COVID-19 have also been observed in many other countries. In Guangzhou, China, a small outbreak, involving less than 100 residents, emerged in March and April 2020, and comprehensive and near-real-time genomic surveillance of SARS-CoV-2 was conducted. When the numbers of confirmed cases among overseas travelers increased, public health measures were enhanced by shifting from self-quarantine to central quarantine and SARS-CoV-2 testing for all overseas travelers. In an analysis of 109 imported cases, we found diverse viral variants distributed in the global viral phylogeny, which were frequently shared within households but not among passengers on the same flight. In contrast to the viral diversity of imported cases, local transmission was predominately attributed to two specific variants imported from Africa, including local cases that reported no direct or indirect contact with imported cases. The introduction events of the virus were identified or deduced before the enhanced measures were taken. These results show the interventions were effective in containing the spread of SARS-CoV-2, and they rule out the possibility of cryptic transmission of viral variants from the first wave in January and February 2020. Our study provides evidence and emphasizes the importance of controls for overseas travelers in the context of the pandemic and exemplifies how viral genomic data can facilitate COVID-19 surveillance and inform public health mitigation strategies.


Assuntos
COVID-19 , SARS-CoV-2 , África , Teste para COVID-19 , China/epidemiologia , Genômica , Humanos
4.
PLoS Negl Trop Dis ; 14(8): e0008541, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32764758

RESUMO

In 2019, dengue incidences increased dramatically in many countries. However, the prospective growth in dengue incidence did not occur in Guangzhou, China. We examined the effectiveness of early start of Grade III response to dengue in Guangzhou. We extracted the data on daily number of dengue cases during 2017-2019 in Guangzhou and weekly data for Foshan and Zhongshan from the China National Notifiable Disease Reporting System, while the data on weekly number of positive ovitraps for adult and larval Aedes albopictus were obtained from Guangzhou Center for Disease Control and Prevention. We estimated the number of dengue cases prevented by bringing forward the starting time of Grade III response from September in 2017-2018 to August in 2019 in Guangzhou using a quasi-Poisson regression model and applied the Baron and Kenny's approach to explore whether mosquito vector density was a mediator of the protective benefit. In Guangzhou, early start of Grade III response was associated with a decline in dengue incidence (relative risk [RR]: 0.54, 95% confidence interval [CI]: 0.43-0.70), with 987 (95% CI: 521-1,593) cases averted in 2019. The rate of positive ovitraps also significantly declined (RR: 0.64, 95% CI: 0.53-0.77). Moreover, both mosquito vector density and early start of Grade III response was significantly associated with dengue incidence after adjustment for each other. By comparing with the incidence in Foshan and Zhongshan where the Grade III response has not been taken, benefits from the response starting in August were confirmed but not if starting from September. Early start of Grade III response has effectively mitigated the dengue burden in Guangzhou, China, which might be partially through reducing the mosquito vector density. Our findings have important public health implications for development and implementation of dengue control interventions for Guangzhou and other locations with dengue epidemics.


Assuntos
Aedes/fisiologia , Dengue/epidemiologia , Mosquitos Vetores/fisiologia , Adulto , Aedes/virologia , Animais , China/epidemiologia , Surtos de Doenças/prevenção & controle , Humanos , Incidência , Larva , Modelos Biológicos , Mosquitos Vetores/virologia
6.
Lancet Infect Dis ; 20(10): 1141-1150, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32562601

RESUMO

BACKGROUND: As of June 8, 2020, the global reported number of COVID-19 cases had reached more than 7 million with over 400 000 deaths. The household transmissibility of the causative pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains unclear. We aimed to estimate the secondary attack rate of SARS-CoV-2 among household and non-household close contacts in Guangzhou, China, using a statistical transmission model. METHODS: In this retrospective cohort study, we used a comprehensive contact tracing dataset from the Guangzhou Center for Disease Control and Prevention to estimate the secondary attack rate of COVID-19 (defined as the probability that an infected individual will transmit the disease to a susceptible individual) among household and non-household contacts, using a statistical transmission model. We considered two alternative definitions of household contacts in the analysis: individuals who were either family members or close relatives, such as parents and parents-in-law, regardless of residential address, and individuals living at the same address regardless of relationship. We assessed the demographic determinants of transmissibility and the infectivity of COVID-19 cases during their incubation period. FINDINGS: Between Jan 7, 2020, and Feb 18, 2020, we traced 195 unrelated close contact groups (215 primary cases, 134 secondary or tertiary cases, and 1964 uninfected close contacts). By identifying households from these groups, assuming a mean incubation period of 5 days, a maximum infectious period of 13 days, and no case isolation, the estimated secondary attack rate among household contacts was 12·4% (95% CI 9·8-15·4) when household contacts were defined on the basis of close relatives and 17·1% (13·3-21·8) when household contacts were defined on the basis of residential address. Compared with the oldest age group (≥60 years), the risk of household infection was lower in the youngest age group (<20 years; odds ratio [OR] 0·23 [95% CI 0·11-0·46]) and among adults aged 20-59 years (OR 0·64 [95% CI 0·43-0·97]). Our results suggest greater infectivity during the incubation period than during the symptomatic period, although differences were not statistically significant (OR 0·61 [95% CI 0·27-1·38]). The estimated local reproductive number (R) based on observed contact frequencies of primary cases was 0·5 (95% CI 0·41-0·62) in Guangzhou. The projected local R, had there been no isolation of cases or quarantine of their contacts, was 0·6 (95% CI 0·49-0·74) when household was defined on the basis of close relatives. INTERPRETATION: SARS-CoV-2 is more transmissible in households than SARS-CoV and Middle East respiratory syndrome coronavirus. Older individuals (aged ≥60 years) are the most susceptible to household transmission of SARS-CoV-2. In addition to case finding and isolation, timely tracing and quarantine of close contacts should be implemented to prevent onward transmission during the viral incubation period. FUNDING: US National Institutes of Health, Science and Technology Plan Project of Guangzhou, Project for Key Medicine Discipline Construction of Guangzhou Municipality, Key Research and Development Program of China.


Assuntos
Busca de Comunicante , Infecções por Coronavirus/transmissão , Características da Família , Pneumonia Viral/transmissão , Adulto , Infecções Assintomáticas/epidemiologia , Número Básico de Reprodução , Betacoronavirus , COVID-19 , China/epidemiologia , Busca de Comunicante/estatística & dados numéricos , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , Quarentena , Estudos Retrospectivos , Fatores de Risco , SARS-CoV-2 , Adulto Jovem
7.
medRxiv ; 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32511590

RESUMO

BACKGROUND: As of April 2, 2020, the global reported number of COVID-19 cases has crossed over 1 million with more than 55,000 deaths. The household transmissibility of SARS-CoV-2, the causative pathogen, remains elusive. METHODS: Based on a comprehensive contact-tracing dataset from Guangzhou, we estimated both the population-level effective reproductive number and individual-level secondary attack rate (SAR) in the household setting. We assessed age effects on transmissibility and the infectivity of COVID-19 cases during their incubation period. RESULTS: A total of 195 unrelated clusters with 212 primary cases, 137 nonprimary (secondary or tertiary) cases and 1938 uninfected close contacts were traced. We estimated the household SAR to be 13.8% (95% CI: 11.1-17.0%) if household contacts are defined as all close relatives and 19.3% (95% CI: 15.5-23.9%) if household contacts only include those at the same residential address as the cases, assuming a mean incubation period of 4 days and a maximum infectious period of 13 days. The odds of infection among children (<20 years old) was only 0.26 (95% CI: 0.13-0.54) times of that among the elderly (≥60 years old). There was no gender difference in the risk of infection. COVID-19 cases were at least as infectious during their incubation period as during their illness. On average, a COVID-19 case infected 0.48 (95% CI: 0.39-0.58) close contacts. Had isolation not been implemented, this number increases to 0.62 (95% CI: 0.51-0.75). The effective reproductive number in Guangzhou dropped from above 1 to below 0.5 in about 1 week. CONCLUSION: SARS-CoV-2 is more transmissible in households than SARS-CoV and MERS-CoV, and the elderly ≥60 years old are the most vulnerable to household transmission. Case finding and isolation alone may be inadequate to contain the pandemic and need to be used in conjunction with heightened restriction of human movement as implemented in Guangzhou.

8.
Sci Total Environ ; 728: 138777, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32330739

RESUMO

OBJECTIVE: To analyze the correlation between climatic factors and the incidence of varicella in Guangzhou, and improve the prevention measures about public health. METHODS: Data for daily climatic variables and varicella incidence from 2006 to 2018 in Guangzhou were collected from the Guangzhou Meteorological Bureau and the National Notifiable Disease Report System. Distributed lag nonlinear models were applied to evaluate the association between climatic factors and varicella incidence. RESULTS: The nonlinear effects of meteorological factors were observed. At lag day21,when the mean temperature was 31.8 °C, the relative risk was the highest as 1.11 (95% CI: 1.07-1.16). When the diurnal temperature range was 24.0 °C at lag day 20, the highest RR was 1.11 (95% CI: 1.05-1.17). For rainfall, the highest RR was 1.09 (95% CI: 1.01-1.19) at lag day 21,when the aggregate rainfall was 160 mm. When air pressure was 1028 hPa, the highest RR was 1.08 (95% CI: 1.04-1.13) at lag day 21. When wind speed was 0.7 m/s, the highest RR was 1.07 (95% CI: 1.04-1.11) at lag day 7. When the hours of sunshine were 9.0 h at lag day 21, the RR was highest as 1.04 (95% CI: 1.02-1.05). Aggregate rainfall, air pressure, and sunshine hours were positively correlated with the incidence of varicella, which was inconsistent with the wind velocity. Mean temperature showed a reverse U-shape curve relationship with varicella, while the diurnal temperature range showed a binomial distribution curve. The extreme effect of climatic factors on the varicella cases was statistically significant, apart from the extremely low effect of rainfall. CONCLUSION: Our preliminary results offered fundamental knowledge which might be benefit to give an insight into epidemic trends of varicella and develop an early warning system. We could use our findings about influential factors to strengthen the intervention and prevention of varicella.


Assuntos
Varicela , China , Humanos , Incidência , Conceitos Meteorológicos , Temperatura
9.
Sci Total Environ ; 663: 227-235, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30711589

RESUMO

OBJECTIVE: To explore the relationship between meteorological factors and scarlet fever incidence from 2006 to 2017 in Guangzhou, the largest subtropical city of Southern China, and assist public health prevention and control measures. METHODS: Data for weekly scarlet fever incidence and meteorological variables from 2006 to 2017 in Guangzhou were collected from the National Notifiable Disease Report System (NNDRS) and the Guangzhou Meteorological Bureau (GZMB). Distributed lag nonlinear models (DLNMs) were conducted to estimate the effect of meteorological factors on weekly scarlet fever incidence in Guangzhou. RESULTS: We observed nonlinear effects of temperature, relative humidity, and wind velocity. The risk was the highest when the weekly mean temperature was 31 °C during lag week 14, yielding a relative risk (RR) of 1.48 (95% CI: 1.01-2.17). When relative humidity was 43.5% during lag week 0, the RR was 1.49 (95% CI: 1.04-2.12); the highest RR (1.55, 95% CI: 1.20-1.99) was reached when relative humidity was 93.5% during lag week 20. When wind velocity was 4.4 m/s during lag week 13, the RR was highest at 3.41 (95% CI: 1.57-7.44). Positive correlations were observed among weekly temperature ranges and atmospheric pressure with scarlet fever incidence, while a negative correlation was detected with aggregate rainfall. The cumulative extreme effect of meteorological variables on scarlet fever incidence was statistically significant, except for the high effect of wind velocity. CONCLUSION: Weekly mean temperature, relative humidity, and wind velocity had double-trough effects on scarlet fever incidence; high weekly temperature range, high atmospheric pressure, and low aggregate rainfall were risk factors for scarlet fever morbidity. Our findings provided preliminary, but fundamental, information that may be useful for a better understanding of epidemic trends of scarlet fever and for developing an early warning system. Laboratory surveillance for scarlet fever should be strengthened in the future.


Assuntos
Umidade , Escarlatina/epidemiologia , Vento , China/epidemiologia , Incidência , Conceitos Meteorológicos , Dinâmica não Linear , Escarlatina/microbiologia , Temperatura , População Urbana/estatística & dados numéricos
10.
BMC Public Health ; 11: 693, 2011 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-21899764

RESUMO

BACKGROUND: Many injection drug users (IDUs) in China have high risk sexual behaviors that contribute to the spread of HIV infection. Although many IDUs in China move through drug rehabilitation centers, this opportunity for sexual health education has largely been overlooked. METHODS: A convenience sample of 667 drug users from two rehabilitation centers in South China was recruited in the study. Two hundred and forty seven drug users from a single Guangdong Province rehabilitation center received the peer-based education intervention, while 420 drug users from another rehabilitation center received routine HIV/STI education and was used as the control. One hundred and eighty nine (22.1%) individuals refused to participate in the study. HIV/STI behavioral and knowledge domains were assessed at 3 months in rehabilitation centers after the intervention (first follow-up) and at 2-23 months in the community after release (second follow-up). RESULTS: Drug users who completed the intervention reported more frequent condom use with casual sex partners (60.0% vs. 12.5% condom use every time, p = 0.011) and less frequent injection (56.7% vs. 26.4% no injection per day, p = 0.008) at the second follow-up compared to those in the routine education group. Loss to follow up was substantial in both control and intervention groups, and was associated with living far from the detention center and having poor HIV knowledge at baseline. CONCLUSIONS: This study shows that rehabilitation centers may be a useful location for providing behavioral HIV/STI prevention services and referral of individuals to community-based programs upon release. More research is needed on behalf of detained drug users in China who have complex social, medical, and legal needs.


Assuntos
Promoção da Saúde/métodos , Grupo Associado , Comportamento de Redução do Risco , Abuso de Substâncias por Via Intravenosa , Adulto , China , Usuários de Drogas , Feminino , Infecções por HIV/prevenção & controle , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Projetos Piloto , Sexo Seguro , Comportamento Sexual , Doenças Sexualmente Transmissíveis/prevenção & controle , Centros de Tratamento de Abuso de Substâncias , Adulto Jovem
11.
Zhonghua Liu Xing Bing Xue Za Zhi ; 27(11): 950-2, 2006 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-17402195

RESUMO

OBJECTIVE: To investigate the dynamic trend of specific antibody against severe acute respiratory syndrome (SARS)-CoV in serum collected at various periods among employees in Guangzhou Xinyuan animal market. METHODS: Volunteers from employees of the animal market were recruited and their serum specific antibody against SARS-CoV were determined by enzyme linked immunesorbent assay (ELISA) method. RESULTS: Positive SARS-CoV specific IgG antibody was found 25.61% (n = 328), 13.03% (n = 238), 12.59% (n = 135), 5.04% (n = 139) and 9.43% (n = 53) among volunteers, which were sampled in May 2003, Dec. 2003, Jan. 2004, July 2004 and June 2005 respectively. No specific IgM antibody was found in all of those samples. Among 129 samples which were tested twice or more, 97 were all negative, 18 all positive, 13 changed from positive to negative but only one sample from negative to positive. When the volunteers were divided by the duration of their working experiences as short-term or long-term, those who had worked at animal market for less than or more then 6 months when being tested, the positive rate for long-term employees were relatively constant, however, all of the persons employed after January 2004, when the palm civets and raccoon dogs were culled from the market, were tested negative. CONCLUSION: The prevalence of specific antibody against SARS-CoV in employees of the animal market were somehow related with the presence or absence of palm civet. No serum was tested positive for persons who were employed after palm civets and raccoon dogs were culled from market. This data indicated that the SARS-CoV might have been from the palm civets and raccoon dog, and the animal market seemed to serve as one of the sources of infection.


Assuntos
Anticorpos Antivirais/análise , Exposição Ocupacional , Vírus da SARS/imunologia , Síndrome Respiratória Aguda Grave , Animais , Comércio , Ensaio de Imunoadsorção Enzimática , Humanos , Cães Guaxinins/virologia , Viverridae/virologia
13.
Zhonghua Liu Xing Bing Xue Za Zhi ; 25(6): 503-5, 2004 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-15231128

RESUMO

OBJECTIVE: To investigate the possible risk factors of severe acute respiratory syndromes coronavirus (SARS-CoV) infection in workers from animal markets. METHODS: Self-designed questionnaires were used and serum samples were tested. Logistic regression analysis was used to analyze the data. RESULTS: Results from simple factor logistic regression analysis showed that jobs which dealing with domestic livestock, wild livestock, wild animals, aquatics were related to risk factors of SARS-CoV infection. Results from multifactor logistic regression analysis showed that jobs that dealing with wild livestock and poultry were important risk factors with OR 12.28 and 0.41. CONCLUSION: Job that dealing with palm civets was the main risk factor of SARS-CoV infection in animal market workers.


Assuntos
Criação de Animais Domésticos , Exposição Ocupacional , Vírus da SARS/isolamento & purificação , Síndrome Respiratória Aguda Grave/epidemiologia , Animais , Portador Sadio/epidemiologia , Portador Sadio/virologia , China/epidemiologia , Reservatórios de Doenças , Humanos , Modelos Logísticos , Aves Domésticas , Fatores de Risco , Vírus da SARS/imunologia , Síndrome Respiratória Aguda Grave/virologia , Inquéritos e Questionários
14.
Zhonghua Yu Fang Yi Xue Za Zhi ; 38(2): 81-3, 2004 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-15061910

RESUMO

OBJECTIVE: To investigate status of infection with severe acute respiratory syndrome coronovirus (SARS-CoV) in traders of wild animals wholesale markets in Guangzhou. METHODS: Serum antibody against SARS-CoV IgG was determined cross-sectionally and symptoms of respiratory infection were investigated retrospectively for part of traders of three wholesale markets for wild animals in Guangzhou. RESULTS: Overall rate of infection with SARS-CoV in 635 traders was 16.69%, varying in three different markets. Infection rate in market A mainly engaging in wild animals ranked the highest of 25.61%, significantly higher than that in markets B and C engaging in domestic fowls and snakes. Infection rate in traders only engaging in civet cats was 58.54%, significantly higher than that in traders engaging in snakes only (9.46%). In market A, infection rate varied in different persons, 59.34%, 20.59%, 16.00%, 15.22%, 10.40% and 9.68% in traders engaging in wild animals, managers, children of the traders, traders engaging in domestic fowls, traders engaging in snakes, and traders engaging in frozen food, respectively, in a decreasing pattern as their contact opportunities. During the period of SARS epidemic, detection rate of SARS-CoV antibody in people with symptoms of acute respiratory infection was higher (30.70%) than that in those without such symptoms (20.08%). Prevalence of symptoms of acute upper respiratory infection in people with positive antibody against SARS-CoV was higher (49.28%) than that in those with negative antibody (30.35%). CONCLUSIONS: Infection with SARS-CoV in traders of animal markets possibly related to their direct exposure to wild animals, particularly to civet cats. During the period of SARS epidemic, some of the traders did infect with SARS-CoV, but they were neglected due to clinically inapparent manifestations.


Assuntos
Imunoglobulina G/sangue , Exposição Ocupacional , Síndrome Respiratória Aguda Grave/imunologia , Animais , Anticorpos Antivirais/sangue , China , Busca de Comunicante , Família , Humanos , Ocupações/classificação , Estudos Retrospectivos , Vírus da SARS/imunologia , Síndrome Respiratória Aguda Grave/transmissão
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