Rapid antigen test as a tool for the identification of SARS-CoV-2 infection and its potential as a self-testing device

ABSTRACT Background: SARS-CoV-2 virus originated in Wuhan (China) in December (2019) and quickly spread worldwide. Antigen tests are rapid diagnostic tests (RDT) that produce results in 15-30 min and are an important tool for the scale-up of COVID-19 testing. COVID-19 diagnostic tests are authorized for self-testing at home in some countries, including Brazil. Widespread COVID-19 diagnostic testing is required to guide public health policies and control the speed of transmission and economic recovery. Methods: Patients with suspected COVID-19 were recruited at the Hospital da Baleia (Belo Horizonte, Brazil). The SARS-CoV-2 antigen-detecting rapid diagnostic tests were evaluated from June 2020 to June 2021 using saliva, nasal, and nasopharyngeal swab samples from 609 patients. Patient samples were simultaneously tested using a molecular assay (RT-qPCR). Sensitivity, specificity, accuracy, and positive and negative predictive values were determined using the statistical program, MedCalc, and GraphPad Prism 8.0. Results: The antigen-detecting rapid diagnostic tests displayed 98% specificity, 60% sensitivity, 96% positive predictive value, and moderate concordance with RT-qPCR. Substantial agreement was found between the two methods for patients tested < 7 days of symptom onset. Conclusions: Our findings support the use of Ag-RDT as a valuable and safe diagnostic method. Ag-RDT was also demonstrated to be an important triage tool for suspected COVID-19 patients in emergencies. Overall, Ag-RDT is an effective strategy for reducing the spread of SARS-CoV-2 and contributing to COVID-19 control.

Fatores associados ao adoecimento por hanseníase em contatos: revisão sistemática e metanálise / Factors associated with the development of leprosy in contacts: a systematic review and meta-analysis

RESUMO Objetivo: Investigar os fatores de risco associados ao adoecimento por hanseníase em contatos de casos da doença. Métodos: Realizou-se uma revisão sistemática e metanálise com busca nas bases de dados: Medical Literature Analysis and Retrieval System Online (MEDLINE), Embase, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Scopus e Web of Science até setembro de 2019. A seleção, a análise e a avaliação da qualidade dos estudos foram realizadas por quatro revisores. Utilizou-se modelo de efeitos aleatórios para calcular o risco relativo agrupado (RR) e intervalos de confiança de 95% (IC95%) quando na presença de heterogeneidade superior a 50%. Resultados: A busca resultou em 2.148 referências e foram incluídos 24 estudos. Estes, em sua maioria, foram realizados no Brasil e na Índia, com delineamento coorte, e incluíram contatos domiciliares, peridomiciliares e sociais. Mostraram-se associados ao adoecimento por hanseníase em contatos: o analfabetismo (RR = 1,48; IC95% 1,22 - 1,79), a convivência intradomiciliar (RR = 2,41; IC95% 1,87 - 3,10) com caso de hanseníase apresentando alta carga bacilar (RR = 2,40; IC95% 1,69 - 3,41), a soropositividade ao antígeno PGL-1(glicolipídeo fenólico-1) do Mycobacterium leprae (RR = 3,54; IC95% 2,21 - 5,67), presença do bacilo na corrente sanguínea (RR = 10,61; IC95% 4,74 - 23,77) e reação de Mitsuda negativa (RR = 2,68; IC95% 1,76 - 4,07). A imunização com bacilo Calmette-Guérin (BCG) teve efeito protetor contra o adoecimento (RR = 0,52; IC95% 0,34 - 0,78). Conclusão: O adoecimento por hanseníase em contatos perpassa pela determinação social, pela susceptibilidade individual e por fragilidades no acesso às ações de controle da doença; contudo, fatores de risco modificáveis são os principais determinantes do adoecimento nessa população.

ABSTRACT Objective: To investigate the risk factors associated with leprosy in contacts of patients. Method: We carried out a systematic review and meta-analysis by searching the databases MEDLINE, Embase, Cochrane Library, CINAHL, LILACS, Scopus, and Web of Science until September 2019. Four reviewers carried out the selection, analysis, and evaluation of quality of studies. The random effects model was used to calculate the pooled relative risk (RR) and 95% confidence intervals (95% CI) when heterogeneity was greater than 50%. Results: The search resulted in 2,148 references and included 24 reports. Most of the studies had been conducted in Brazil and India, had a cohort design and included household, neighbors, and social contacts. The risk factors associated with illness due to leprosy in contacts were: illiteracy (RR = 1,48; 95%CI 1,22 - 1,79), living in the same house (RR = 2,41; 95%CI 1,87 - 3,10) of a case of leprosy with high bacillary load (RR = 2.40; 95%CI 1.69 - 3.41), seropositivity to the Mycobacterium leprae PGL-1 (phenolic glycolipid-1) antigen (RR = 3.54; 95%CI 2.21 - 5.67), presence of the bacillus in the bloodstream (RR = 10.61; 95%CI 4.74 - 23.77) and negative Mitsuda reaction (RR = 2,68; 95%CI 1,76 - 4,07). Immunization with BCG (bacillus Calmette-Guérin) vaccine had a protective effect against leprosy. Conclusion: Leprosy in contacts of patients involves social determination, individual susceptibility, and difficulties in access to disease control actions, but modifiable risk factors are the main determinants of illness in this population.