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1.
Epidemiol Infect ; 149: e91, 2021 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-33849684

RESUMO

An outbreak of SARS-CoV2 infection in a Barcelona prison was studied. One hundred and forty-eight inmates and 36 prison staff were evaluated by rt-PCR, and 24.1% (40 prisoners, two health workers and four non-health workers) tested positive. In all, 94.8% of cases were asymptomatic. The inmates were isolated in prison module 4, which was converted into an emergency COVID unit. There were no deaths. Generalised screening and the isolation and evaluation of the people infected were key measures. Symptom-based surveillance must be supplemented by rapid contact-based monitoring in order to avoid asymptomatic spread among prisoners and the community at large.


Assuntos
/epidemiologia , Portador Sadio/epidemiologia , Controle de Infecções , Prisões , Saúde Pública , Quarentena , Adulto , Idoso , /prevenção & controle , Portador Sadio/diagnóstico , Portador Sadio/prevenção & controle , Surtos de Doenças , Pessoal de Saúde , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Prisioneiros , Índice de Gravidade de Doença , Espanha/epidemiologia , Adulto Jovem
3.
Ital J Pediatr ; 47(1): 65, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33712061

RESUMO

BACKGROUND: Children often develop an asymptomatic form of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), but it is debated if children are at higher risk than adults to be asymptomatic carriers of SARS-CoV-2, especially during the school reopening. The main aim of this study was to investigate the frequency of SARS-CoV-2 asymptomatic carriers in children and adults during the reopening of the schools in Milan, Italy. METHODS: We conducted a cross-sectional study at the pediatric and adult Emergency Department (ED) of the Ca' Granda Ospedale Maggiore Policlinico (Milan) between October 1 and 31, 2020, i.e. 3 weeks after the reopening of schools. Patients admitted to the ED short stay observation and without any sign or symptom consistent with a SARS-CoV-2 were eligible. These patients underwent a nasopharyngeal swab specimen for the detection of SARS-CoV-2. The odds ratio and its 95% confidence interval (CI) was calculated to assess the risk of asymptomatically carrying the SARS-CoV-2 infection in children and adults. RESULTS: A total of 69 (27 females, median age 8.7 years) children and 251 (107 females, median age 71 years) adults were enrolled. Pediatric and adult subjects tested positive for SARS-CoV-2 with a similar frequency (1/69 [1.4%] vs 4/251 [1.6%]). Children had an odds ratio to be a carrier of 0.91 (CI 0.02- 9.38) compared to adults. CONCLUSIONS: The frequency of asymptomatic SARS-CoV-2 carriers was similar among children and adults. Considering the emerging diffusion of new SARS-CoV-2 variants, the asymptomatic spread of SARS-CoV-2 infection among children and adults should be monitored.


Assuntos
/epidemiologia , Portador Sadio/diagnóstico , Adolescente , Idoso , Idoso de 80 Anos ou mais , Portador Sadio/epidemiologia , Criança , Pré-Escolar , Estudos Transversais , Serviço Hospitalar de Emergência , Feminino , Humanos , Lactente , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Nasofaringe/virologia , Instituições Acadêmicas , Manejo de Espécimes
4.
Elife ; 102021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33779548

RESUMO

Here, we develop a simple molecular test for SARS-CoV-2 in saliva based on reverse transcription loop-mediated isothermal amplification. The test has two steps: (1) heat saliva with a stabilization solution and (2) detect virus by incubating with a primer/enzyme mix. After incubation, saliva samples containing the SARS-CoV-2 genome turn bright yellow. Because this test is pH dependent, it can react falsely to some naturally acidic saliva samples. We report unique saliva stabilization protocols that rendered 295 healthy saliva samples compatible with the test, producing zero false positives. We also evaluated the test on 278 saliva samples from individuals who were infected with SARS-CoV-2 but had no symptoms at the time of saliva collection, and from 54 matched pairs of saliva and anterior nasal samples from infected individuals. The Saliva TwoStep test described herein identified infections with 94% sensitivity and >99% specificity in individuals with sub-clinical (asymptomatic or pre-symptomatic) infections.


Assuntos
/diagnóstico , Portador Sadio/diagnóstico , Portador Sadio/virologia , Saliva/virologia , /metabolismo , Humanos , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Viral/genética , Sensibilidade e Especificidade , Manejo de Espécimes/métodos
6.
BMC Pregnancy Childbirth ; 21(1): 212, 2021 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-33731037

RESUMO

BACKGROUND: Asymptomatic carriage of COVID-19 in pregnant women has been reported and could lead to outbreaks in maternity units. We sought to ascertain the impact of rapid isothernal nucleic acid based testing for COVID-19 in an unselected cohort of pregnant women attending our maternity unit. We also assessed the correlation between community prevalence and asymptomatic carriage. METHODS: Data for the retrospective cohort study were collected from a large UK tertiary maternity unit over a 4-week period using computerised hospital records. Literature searches were performed across multiple repositories. COVID-19 prevalence was extracted from online repositories. RESULTS: Nasopharyngeal and oropharyngeal swabs were obtained from 457/465 (98%) women during the study period. The median turnaround time for results was 5.3 h (interquartile range (IQR) 2.6-8.9 h), with 92% of the results returned within 24 h. In our cohort, only one woman tested positive, giving a screen positive rate of 0.22% (1/457; 95% CI: 0.04-1.23%). One woman who tested negative developed a fever postnatally following discharge but was lost to follow-up. From our literature review, we did not find any correlation between asymptomatic carriage in pregnant women and the reported regional prevalence of COVID-19. CONCLUSIONS: Testing using the SAMBA-II machine was acceptable to the vast majority of pregnant women requiring admission and had a low turnaround time. Asymptomatic carriage is low, but not correlated to community prevalence rates. Screening pregnant women on admission will remain an important component in order to minimise nosocomial infection.


Assuntos
/métodos , Portador Sadio/diagnóstico , Infecção Hospitalar/prevenção & controle , Complicações Infecciosas na Gravidez/diagnóstico , /epidemiologia , Portador Sadio/epidemiologia , Estudos de Coortes , Feminino , Maternidades , Humanos , Programas de Rastreamento , Testes Imediatos , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Estudos Retrospectivos , Fatores de Tempo , Reino Unido/epidemiologia
7.
Curr Oncol ; 28(1): 847-852, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33567626

RESUMO

The pandemic of SARS-CoV-2 is a serious global challenge affecting millions of people worldwide. Cancer patients are at risk for infection exposure and serious complications. A prompt diagnosis of SARS-CoV-2 infection is crucial for the timely adoption of isolation measures and the appropriate management of cancer treatments. In lung cancer patients the symptoms of infection 19 may resemble those exhibited by the underlying oncologic condition, possibly leading to diagnostic overlap and delays. Moreover, cancer patients might display a prolonged positivity of nasopharyngeal RT-PCR assays for SARS-CoV-2, causing long interruptions or delay of cancer treatments. However, the association between the positivity of RT-PCR assays and the patient's infectivity remains uncertain. We describe the case of a patient with non-small cell lung cancer, and a severe ab extrinseco compression of the trachea, whose palliative radiotherapy was delayed because of the prolonged positivity of nasopharyngeal swabs for SARS-CoV-2. The patient did not show clinical symptoms suggestive of active infection, but the persistent positivity of RT-PCR assays imposed the continuation of isolation measures and the delay of radiotherapy for over two months. Finally, the negative result of SARS-CoV-2 viral culture allowed us to verify the absence of viral activity and to rule out the infectivity of the patient, who could finally continue her cancer treatment.


Assuntos
/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/virologia , Neoplasias Pulmonares/virologia , /isolamento & purificação , Idoso , Portador Sadio/diagnóstico , Feminino , Humanos , Nasofaringe/virologia , RNA Viral/genética , Tempo para o Tratamento
8.
JAMA Netw Open ; 4(2): e210202, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33630090

RESUMO

Importance: Owing to concerns of coronavirus disease 2019 (COVID-19) outbreaks, many congregant settings are forced to close when cases are detected because there are few data on the risk of different markers of transmission within groups. Objective: To determine whether symptoms and laboratory results on the first day of COVID-19 diagnosis are associated with development of a case cluster in a congregant setting. Design, Setting, and Participants: This cohort study of trainees with COVID-19 from May 11 through August 24, 2020, was conducted at Joint Base San Antonio-Lackland, the primary site of entry for enlistment in the US Air Force. Symptoms and duration, known contacts, and cycle threshold for trainees diagnosed by reverse transcription-polymerase chain reaction were collected. A cycle threshold value represents the number of nucleic acid amplification cycles that occur before a specimen containing the target material generates a signal greater than the predetermined threshold that defines positivity. Cohorts with 5 or more individuals with COVID-19 infection were defined as clusters. Participants included 10 613 trainees divided into 263 parallel cohorts of 30 to 50 people arriving weekly for 7 weeks of training. Exposures: All trainees were quarantined for 14 days on arrival. Testing was performed on arrival, on day 14, and anytime during training when indicated. Protective measures included universal masking, physical distancing, and rapid isolation of trainees with COVID-19. Main Outcomes and Measures: Association between days of symptoms, specific symptoms, number of symptoms, or cycle threshold values of individuals diagnosed with COVID-19 via reverse transcription-polymerase chain reaction and subsequent transmission within cohorts. Results: In this cohort study of 10 613 US Air Force basic trainees in 263 cohorts, 403 trainees (3%) received a diagnosis of COVID-19 in 129 cohorts (49%). Among trainees with COVID-19 infection, 318 (79%) were men, and the median (interquartile range [IQR]) age was 20 (19-23) years; 204 (51%) were symptomatic, and 199 (49%) were asymptomatic. Median (IQR) cycle threshold values were lower in symptomatic trainees compared with asymptomatic trainees (21.2 [18.4-27.60] vs 34.8 [29.3-37.4]; P < .001). Cohorts with clusters of individuals with COVID-19 infection were predominantly men (204 cohorts [89%] vs 114 cohorts [64%]; P < .001), had more symptomatic trainees (146 cohorts [64%] vs 53 cohorts [30%]; P < .001), and had more median (IQR) symptoms per patient (3 [2-5] vs 1 [1-2]; P < .001) compared with cohorts without clusters. Within cohorts, subsequent development of clusters of 5 or more individuals with COVID-19 infection compared with those that did not develop clusters was associated with cohorts that had more symptomatic trainees (31 of 58 trainees [53%] vs 43 of 151 trainees [28%]; P = .001) and lower median (IQR) cycle threshold values (22.3 [18.4-27.3] vs 35.3 [26.5-37.8]; P < .001). Conclusions and Relevance: In this cohort study of US Air Force trainees living in a congregant setting during the COVID-19 pandemic, higher numbers of symptoms and lower cycle threshold values were associated with subsequent development of clusters of individuals with COVID-19 infection. These values may be useful if validated in future studies.


Assuntos
/métodos , Militares/estatística & dados numéricos , /diagnóstico , /fisiopatologia , Portador Sadio/diagnóstico , Portador Sadio/epidemiologia , Portador Sadio/transmissão , Estudos de Coortes , Tosse/fisiopatologia , Feminino , Cefaleia/fisiopatologia , Humanos , Masculino , Mialgia/fisiopatologia , Faringite/fisiopatologia , Características de Residência , Fatores de Risco , Índice de Gravidade de Doença , Estados Unidos/epidemiologia , Adulto Jovem
9.
Emerg Infect Dis ; 27(4): 1249-1251, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33567246

RESUMO

We report an imported case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant P.1 detected in an asymptomatic traveler who arrived in Italy on an indirect flight from Brazil. This case shows the risk for introduction of SARS-CoV-2 variants from indirect flights and the need for continued SARS-CoV-2 surveillance.


Assuntos
Doenças Transmissíveis Importadas , Programas de Triagem Diagnóstica , Glicoproteína da Espícula de Coronavírus/genética , Adulto , Brasil/epidemiologia , /epidemiologia , /virologia , Portador Sadio/diagnóstico , Portador Sadio/epidemiologia , Doenças Transmissíveis Importadas/diagnóstico , Doenças Transmissíveis Importadas/epidemiologia , Doenças Transmissíveis Importadas/virologia , Programas de Triagem Diagnóstica/organização & administração , Programas de Triagem Diagnóstica/normas , Humanos , Itália/epidemiologia , Masculino , Mutação , /isolamento & purificação , Viagem/estatística & dados numéricos , Doença Relacionada a Viagens
10.
PLoS One ; 16(2): e0240524, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33626039

RESUMO

Managing the pandemic caused by SARS-CoV-2 requires new capabilities in testing, including the possibility of identifying, in minutes, infected individuals as they enter spaces where they must congregate in a functioning society, including workspaces, schools, points of entry, and commercial business establishments. Here, the only useful tests (a) require no sample transport, (b) require minimal sample manipulation, (c) can be performed by unlicensed individuals, (d) return results on the spot in much less than one hour, and (e) cost no more than a few dollars. The sensitivity need not be as high as normally required by the FDA for screening asymptomatic carriers (as few as 10 virions per sample), as these viral loads are almost certainly not high enough for an individual to present a risk for forward infection. This allows tests specifically useful for this pandemic to trade-off unneeded sensitivity for necessary speed, simplicity, and frugality. In some studies, it was shown that viral load that creates forward-infection risk may exceed 105 virions per milliliter, easily within the sensitivity of an RNA amplification architecture, but unattainable by antibody-based architectures that simply target viral antigens. Here, we describe such a test based on a displaceable probe loop amplification architecture.


Assuntos
/métodos , Portador Sadio/virologia , /isolamento & purificação , Adulto , Antígenos Virais/genética , /epidemiologia , Portador Sadio/diagnóstico , Feminino , Humanos , Masculino , Técnicas de Amplificação de Ácido Nucleico/métodos , Pandemias , RNA Viral/genética , Sensibilidade e Especificidade , Carga Viral
12.
J Hosp Infect ; 111: 89-95, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33453349

RESUMO

BACKGROUND: COVID-19 care home outbreaks represent a significant proportion of COVID-19 morbidity and mortality in the UK. National testing initially focused on symptomatic care home residents, before extending to asymptomatic cohorts. AIM: The aim was to describe the epidemiology and transmission of COVID-19 in outbreak free care homes. METHODS: A two-point prevalence survey of COVID-19, in 34 Liverpool care homes, was performed in April and May 2020. Changes in prevalence were analysed. Associations between care home characteristics, reported infection, prevention and control interventions, and COVID-19 status were described and analysed. FINDINGS: No resident developed COVID-19 symptoms during the study. There was no significant difference between: the number of care homes containing at least one test positive resident between the first (17.6%, 95% confidence interval (CI) 6.8-34.5) and second round (14.7%, 95% CI 5.0-31.1) of testing (p>0.99); and the number of residents testing positive between the first (2.1%, 95% CI 1.2-3.4) and second round (1.0%, 95% CI 0.5-2.1) of testing (P=0.11). Care homes providing nursing care (risk ratio (RR) 7.99, 95% CI 1.1-57.3) and employing agency staff (RR 8.4, 95% CI 1.2-60.8) were more likely to contain test positive residents. Closing residents shared space was not associated with residents testing positive (RR 2.63, 95% CI 0.4-18.5). CONCLUSIONS: Asymptomatic COVID-19 care homes showed no evidence of disease transmission or development of outbreaks; suggesting that current infection prevention and control measures are effective in preventing transmission. Repeat testing at two to three weeks had limited or no public health benefits over regular daily monitoring of staff and residents for symptoms. These results should inform policies calling for regular testing of asymptomatic residents.


Assuntos
/estatística & dados numéricos , /transmissão , Portador Sadio/diagnóstico , Surtos de Doenças/prevenção & controle , Instituição de Longa Permanência para Idosos/estatística & dados numéricos , Casas de Saúde/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções Assintomáticas/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Sintomas , Reino Unido/epidemiologia
13.
PLoS One ; 16(1): e0244716, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33507960

RESUMO

University students, especially those living in dormitories, are known to have a high risk of invasive meningococcal disease. We performed a longitudinal study to investigate the change in Neisseria meningitidis carriage rates and identify the risk factors for carriage acquisition in university students in South Korea. We recruited university entrants who were admitted to a student dormitory. Pharyngeal swabs were taken from participants at baseline, 1 month, and 3 months, and the subjects completed a questionnaire. Culture and real-time polymerase chain reaction (PCR) for species-specific ctrA and sodC genes were performed. The cultured isolates or PCR-positive samples were further evaluated for epidemiologic characterization using serogrouping, PorA typing, FetA typing, and multilocus sequence typing (MLST). At the first visit, we enrolled 332 participants who were predominantly male (64.2%) with a median age of 19 years. Meningococcal carriage rates increased from 2.7% (95% confidence interval [CI] 0.9-4.4%) at baseline to 6.3% (95% CI 3.4-9.0%) at 1 month and 11.8% (95% CI 7.8-15.6%) at 3 months. Nongroupable isolates accounted for 50.0% of all isolates, with serogroup B being the next most prevalent (24.1%). In the study population, male sex (OR 2.613, 95% CI 1.145-5.961, p = 0.022) and frequent pub or club visits (OR 3.701, 95% CI 1.536-8.919, p = 0.004) were significantly associated with meningococcal carriage. Based on serotype and MLST analyses, six carriers transmitted meningococci to other study participants. N. meningitidis carriage rates among new university entrants who lived in a dormitory significantly increased within the first 3 months of dormitory stay, probably owing to the transmission of identical genotype among students. Based on the risk of meningococcal disease, meningococcal vaccination should be considered for students before dormitory admission.


Assuntos
Infecções Meningocócicas/diagnóstico , Infecções Meningocócicas/epidemiologia , Neisseria meningitidis/isolamento & purificação , Adolescente , Adulto , Técnicas de Tipagem Bacteriana , Portador Sadio/diagnóstico , Portador Sadio/epidemiologia , Feminino , Humanos , Estudos Longitudinais , Masculino , Tipagem de Sequências Multilocus , Neisseria meningitidis/genética , Estudos Prospectivos , República da Coreia/epidemiologia , Estudantes , Universidades , Adulto Jovem
14.
ANZ J Surg ; 91(1-2): 27-32, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33421257

RESUMO

BACKGROUND: The study aimed to estimate the prevalence of active or previous SARS-CoV-2 infection in asymptomatic adults admitted for elective surgery in Australian hospitals. This surveillance activity was established as part of the National Pandemic Health Intelligence Plan. METHODS: Participants (n = 3037) were recruited from 11 public and private hospitals in four states (NSW, Vic, SA and WA) between 2 June and 17 July 2020, with an overall 66% participation rate. Presence of SARS-CoV-2 viral RNA was assessed by Reverse Transcriptase - Polymerase Chain Reaction (RT-PCR) analysis of nasopharyngeal swabs taken after induction of anaesthesia. Presence of anti-SARS-CoV-2 antibodies was assessed by analysis of serum collected at the same time using a novel dual-antigen ELISA assay. RESULTS: No patient (0/3010) returned a positive RT-PCR result. The Bayesian estimated prevalence of active infection of 0.02% (95% probability interval 0.00-0.11%), with the upper endpoint being 1 in 918. Positive serology (IgG) was observed in 15 of 2991 patients, with a strong positive in five of those individuals (Bayesian estimated seroprevalence 0.16%; 95% probability interval 0.00-0.47%). CONCLUSION: These results confirm that during periods of low community prevalence of SARS-CoV-2 elective surgery patients without fever or respiratory symptoms had a very low prevalence of active SARS-CoV-2 infection.


Assuntos
/epidemiologia , Portador Sadio/epidemiologia , Procedimentos Cirúrgicos Eletivos , Hospitalização , Adulto , Idoso , Idoso de 80 Anos ou mais , Austrália , Portador Sadio/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa
15.
PLoS One ; 15(12): e0244450, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33382792

RESUMO

OBJECTIVES: To study Group B Streptococcus (GBS) isolates associated with different clinical syndromes: asymptomatic carriage in pregnant women, intrauterine fetal death (IUFD), and early onset disease (EOD) in the newborn. METHODS: GBS isolates were collected from asymptomatic pregnant women admitted for labor, IUFD cases, and neonates with EOD. Serotypes and antibiotic susceptibilities were determined. Multilocus sequence typing (MLST) was performed to assess genetic epidemiology. RESULTS: GBS carriage rate was 26.1% (280/1074). The dominant serotype among asymptomatic pregnant women was VI [98/240 women (40.8%)], followed by serotypes III, V and IV in 42/240 (17.5%), 30/240 (12.5%) and 28/240 (11.7%) women, respectively. The dominant serotype in IUFD cases was serotype VI [10/13 (76.9%)]. In contrast the prevalent serotype among EOD cases was III [16/19 (84.2%)]. ST-1 was associated with IUFD [7/13 (53.8%)], ST-17 was associated with serotype III and EOD in the newborn 14/19 (73.7%)]. Erythromycin and clindamycin resistance reached 36.8%, 7.7% and 20.0%among EOD, vaginal carriage and IUFD, respectively. CONCLUSIONS: Serotypes VI and ST-1 were dominant among asymptomatic pregnant women and in IUFD cases while EOD was associated with serotype III and ST-17. Invasive mechanisms thus may differ between IUFD and EOD in the newborn and virulence may be related to capsule serotype. Resistance rates to erythromycin and clindamycin were high in EOD cases.


Assuntos
Portador Sadio/diagnóstico , Morte Fetal , Sepse Neonatal/diagnóstico , Complicações Infecciosas na Gravidez/diagnóstico , Infecções Estreptocócicas/diagnóstico , Streptococcus agalactiae/genética , Adulto , Idade de Início , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Portador Sadio/tratamento farmacológico , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Clindamicina/farmacologia , Clindamicina/uso terapêutico , Farmacorresistência Bacteriana Múltipla/genética , Eritromicina/farmacologia , Eritromicina/uso terapêutico , Feminino , Humanos , Recém-Nascido , Tipagem de Sequências Multilocus , Sepse Neonatal/tratamento farmacológico , Sepse Neonatal/epidemiologia , Sepse Neonatal/microbiologia , Polissacarídeos Bacterianos/genética , Gravidez , Complicações Infecciosas na Gravidez/tratamento farmacológico , Complicações Infecciosas na Gravidez/epidemiologia , Complicações Infecciosas na Gravidez/microbiologia , Sorogrupo , Sorotipagem , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/epidemiologia , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae/isolamento & purificação , Streptococcus agalactiae/patogenicidade , Virulência/genética , Adulto Jovem
17.
PLoS One ; 15(12): e0244475, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33378344

RESUMO

The alarming spread of the pandemic coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus requires several measures to reduce the risk of contagion. Every successful strategy in controlling the SARS-CoV-2 infection depends on timely diagnosis, which should include testing of asymptomatic carriers. Consequently, increasing the throughput for clinical laboratories for the purposes of conducting large-scale diagnostic testing is urgently needed. Here we support the hypothesis that standard diagnostic protocol for SARS-CoV-2 virus could be conveniently applied to pooled samples obtained from different subjects. We suggest that a two-step sequential pooling procedure could identify positive subjects, ensuring at the same time significant benefits of cost and time. The simulation data presented herein were used to assess the efficiency, in terms of number of required tests, both for random assignment of the subjects to the pools and for situations in which epidemiological and clinical data are used to create "informed" pools. Different scenarios were simulated to measure the effect of different pool sizes and different values for virus frequency. Our results allow for a customization of the pooling strategy according to the specific characteristics of the cohort being tested.


Assuntos
/métodos , Manejo de Espécimes/métodos , Portador Sadio/diagnóstico , Testes Diagnósticos de Rotina/métodos , Humanos
18.
BMC Infect Dis ; 20(1): 798, 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33115434

RESUMO

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), the causative agent of the coronavirus disease 19 (COVID-19), is a highly transmittable virus. Since the first person-to-person transmission of SARS-CoV-2 was reported in Italy on February 21st, 2020, the number of people infected with SARS-COV-2 increased rapidly, mainly in northern Italian regions, including Piedmont. A strict lockdown was imposed on March 21st until May 4th when a gradual relaxation of the restrictions started. In this context, computational models and computer simulations are one of the available research tools that epidemiologists can exploit to understand the spread of the diseases and to evaluate social measures to counteract, mitigate or delay the spread of the epidemic. METHODS: This study presents an extended version of the Susceptible-Exposed-Infected-Removed-Susceptible (SEIRS) model accounting for population age structure. The infectious population is divided into three sub-groups: (i) undetected infected individuals, (ii) quarantined infected individuals and (iii) hospitalized infected individuals. Moreover, the strength of the government restriction measures and the related population response to these are explicitly represented in the model. RESULTS: The proposed model allows us to investigate different scenarios of the COVID-19 spread in Piedmont and the implementation of different infection-control measures and testing approaches. The results show that the implemented control measures have proven effective in containing the epidemic, mitigating the potential dangerous impact of a large proportion of undetected cases. We also forecast the optimal combination of individual-level measures and community surveillance to contain the new wave of COVID-19 spread after the re-opening work and social activities. CONCLUSIONS: Our model is an effective tool useful to investigate different scenarios and to inform policy makers about the potential impact of different control strategies. This will be crucial in the upcoming months, when very critical decisions about easing control measures will need to be taken.


Assuntos
Controle de Doenças Transmissíveis/métodos , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , Betacoronavirus/isolamento & purificação , Portador Sadio/diagnóstico , Portador Sadio/epidemiologia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/transmissão , Suscetibilidade a Doenças/diagnóstico , Suscetibilidade a Doenças/epidemiologia , Humanos , Itália/epidemiologia , Modelos Teóricos , Pneumonia Viral/diagnóstico , Pneumonia Viral/transmissão , Quarentena
19.
Sci Adv ; 6(37)2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32917716

RESUMO

Recent reports suggest that 10 to 30% of severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) infected patients are asymptomatic and that viral shedding may occur before symptom onset. Therefore, there is an urgent need to increase diagnostic testing capabilities to prevent disease spread. We developed P-BEST, a method for Pooling-Based Efficient SARS-CoV-2 Testing, which identifies all positive subjects within a set of samples using a single round of testing. Each sample is assigned into multiple pools using a combinatorial pooling strategy based on compressed sensing. We pooled sets of 384 samples into 48 pools, providing both an eightfold increase in testing efficiency and an eightfold reduction in test costs, while identifying up to five positive carriers. We then used P-BEST to screen 1115 health care workers using 144 tests. P- BEST provides an efficient and easy-to-implement solution for increasing testing capacity that can be easily integrated into diagnostic laboratories.


Assuntos
Infecções Assintomáticas , Portador Sadio/diagnóstico , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Betacoronavirus/isolamento & purificação , Portador Sadio/virologia , Humanos , Pandemias , Eliminação de Partículas Virais
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