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BACKGROUND: The emergence of variants of concern (VOCs) requires an ongoing assessment of the performance of antigen lateral flow tests (Ag-RDTs). The limit of detection (LOD) of 32 Ag-RDTs was evaluated using the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Gamma variant. METHODS: Ag-RDTs were performed according to the manufacturer's instructions with a clinical isolate of the Gamma variant. RESULTS: Twenty-eight of the 32 Ag-RDTs exceeded the World Health Organization criteria. CONCLUSIONS: This comprehensive analytical evaluation of Ag-RDTs demonstrated that the test performance was maintained with Gamma VOC.
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COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Humanos , Sensibilidade e EspecificidadeRESUMO
ABSTRACT Background: The emergence of variants of concern (VOCs) requires an ongoing assessment of the performance of antigen lateral flow tests (Ag-RDTs). The limit of detection (LOD) of 32 Ag-RDTs was evaluated using the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Gamma variant. Methods: Ag-RDTs were performed according to the manufacturer's instructions with a clinical isolate of the Gamma variant. Results: Twenty-eight of the 32 Ag-RDTs exceeded the World Health Organization criteria. Conclusions: This comprehensive analytical evaluation of Ag-RDTs demonstrated that the test performance was maintained with Gamma VOC.
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BACKGROUND: Detailed information on how socio-economic characteristics are related to COVID-19 incident cases and maternal deaths is needed. We investigated the spatial distribution of COVID-19 cases and maternal deaths in Brazil and their association with social determinants of health. METHODS: This was a population-based ecological study with a spatial analysis of all cases and deaths of COVID-19 in the obstetric population. Data on COVID-19 cases and deaths in the obstetric population, social vulnerability, health inequities, and health system capacity at the municipal level were obtained from several publicly sources in Brazil. A Bayesian empirical local model was used to identify fluctuations of the indicators. Spatial statistic tests were used to identity the spatial clusters and measure the municipalities' risk of COVID-19 in the obstetric population. Beta regression was used to characterise the association between socio-economic indicators and the burden of COVID-19. FINDINGS: A total of 13,858 cases and 1,396 deaths due to COVID-19 were recorded in Brazil from March 2020 to June 2021. There was a variation in the number of cases per municipality, with 105 municipalities with rates from 2,210 to 3,884 cases and 45 municipalities with rates from 3,884 to 7,418 cases per 100,000 live births. The maternal mortality ratio also varied widely across municipalities. There was a spatial dependence on smoothed maternal mortality rates (I Moran 0â¢10; P = 0â¢010), and 15 municipalities had higher risk of maternal deaths. Municipalities characterized by lower health resources and higher socioeconomic inequalities presented the highest rates of incidence and maternal mortality by COVID-19. INTERPRETATION: In Brazil, COVID-19 cases and deaths in the obstetric population had a heterogeneous geographical distribution, with well-defined spatial clusters mostly located in the countryside. Municipalities with a high degree of socioeconomic dissimilarities showed higher maternal mortality rates than areas with better social and infrastructure indicators. FUNDING: None.
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Dengue fever occurs worldwide and about 1% of cases progress to severe haemorrhage and shock. Dengue is endemic in Guatemala and its surveillance system could document long term trends. We analysed 17 years of country-wide dengue surveillance data in Guatemala to describe epidemiological trends from 2000 to 2016.Data from the national dengue surveillance database were analysed to describe dengue serotype frequency, seasonality, and outbreaks. We used Poisson regression models to compare the number of cases each year with subsequent years and to estimate incidence ratios within serotype adjusted by age and gender. 91,554 samples were tested. Dengue was confirmed by RT-qPCR, culture or NS1-ELISA in 7097 (7.8%) cases and was IgM ELISA-positive in 19,290 (21.1%) cases. DENV1, DENV2, DENV3, and DENV4 were detected in 2218 (39.5%), 2580 (45.9%), 591 (10.5%), and 230 (4.1%) cases. DENV1 and DENV2 were the predominant serotypes, but all serotypes caused epidemics. The largest outbreak occurred in 2010 with 1080 DENV2 cases reported. The incidence was higher among adults during epidemic years, with significant increases in 2005, 2007, and 2013 DENV1 outbreaks, the 2010 DENV2 and 2003 DENV3 outbreaks. Adults had a lower incidence immediately after epidemics, which is likely linked to increased immunity.
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Dengue/diagnóstico , Dengue/epidemiologia , Adolescente , Adulto , Anticorpos Antivirais/imunologia , Criança , Pré-Escolar , Dengue/imunologia , Vírus da Dengue/imunologia , Surtos de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Guatemala/epidemiologia , Humanos , Incidência , Lactente , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Sorogrupo , Sorotipagem/métodos , Adulto JovemRESUMO
Chikungunya was introduced into the Americas in 2015 causing a pandemic across the continent. Testing during the acute phase of infection relies on qRT-PCR, but available assays have a number of limitations. A qRT-PCR assay specific to the chikungunya E1 gene was designed using sequence data from contemporary strains. A probit analysis established the 95% limit of detection as 19.6 copies per reaction. We compared the assay with a US Centers for Disease Control (CDC) chikungunya qRT-PCR as the reference standard. The assay had a sensitivity and specificity of 98.4% and 100% in 90 samples retrospectively collected in Guatemala. In a further 74 febrile samples prospectively collected in Ecuador and Guatemala the test had a sensitivity and specificity of 100% and 98.4%, respectively. Sequencing the nsp4 gene of the discordant positive sample indicated the presence of chikungunya RNA, and mismatches to the primer binding sites of the CDC assay.
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Febre de Chikungunya/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Equador , Feminino , Guatemala , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Sensibilidade e Especificidade , Adulto JovemRESUMO
We screened serum samples referred to the national reference laboratory in Guatemala that were positive for chikungunya or dengue viruses in June 2015. Co-infection with both viruses was detected by reverse transcription PCR in 46 (32%) of 144 samples. Specimens should be tested for both arboviruses to detect co-infections.