Development and characterization of a quantitative ELISA to detect anti-SARS-CoV-2 spike antibodies.

A novel clinical assay for the detection and quantitation of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was adapted from an in-house, research-based enzyme-linked immunosorbent assay (ELISA). Development and validation were performed under regulatory guidelines, and the test obtained emergency use authorization (EUA) from the New York State Department of Health (NYSDOH) and the Food and Drug Administration (FDA). The Mount Sinai coronavirus disease 2019 (COVID-19) antibody assay is an orthogonal, quantitative direct ELISA test which detects antibodies reactive to the receptor binding domain (RBD) and the spike protein of the novel SARS-CoV-2. The assay is performed on 96-well plates coated with either SARS-CoV-2 recombinant RBD or spike proteins. The test is divided into two stages, a qualitative screening assay against RBD and a quantitative assay against the full-length spike protein. The test uses pooled high titer serum as a reference standard. Negative pre-COVID-19 and positive post-COVID-19, PCR-confirmed specimens were incorporated in each ELISA test run, and the assays were performed independently at two different locations. The Mount Sinai COVID-19 serology performed with high sensitivity and specificity, 92.5% (95% CI: 0.785-0.980) and 100% (CI: 0.939-1.000) respectively. Between-run precision was assessed with a single run repeated over 22 days; and within-run precision was assessed with 10 replicates per day over 22 days. Both were within reported acceptance criteria (CV ≤ 20%). This population-based study reveals the applicability and reliability of this novel orthogonal COVID-19 serology test for the detection and quantitation of antibodies against SARS-CoV-2, allowing a broad set of clinical applications, including the broad evaluation of SARS-CoV-2 seroprevalence and antibody profiling in different population subsets.

Construcción y validación de un instrumento para la evaluación de la calidad de vida en personas con VIH / Construction and validation of an instrument to assess quality of life in persons with HIV

Entre los meses de abril de 2006 y mayo de 2007 se realizó un estudio transversal cuyo objetivo fue el de probar las propiedades psicométricas de un instrumento para la evaluación de la calidad de vida en personas con VIH. Participaron 149 personas con VIH pertenecientes a dos instituciones del sector salud que se localizan en dos ciudades del noroeste de México, a quienes se administró un instrumento que consta de 29 preguntas agrupadas en tres dominios: salud física, salud psicológica y habilidades personales y sociales. Para el tratamiento de los datos se utilizaron los siguientes procedimientos: la prueba de la t de Student para valorar el nivel de comprensión de las preguntas; un análisis factorial exploratorio con rotación varimax (normalización con Kaiser) para la validez de constructo; el coeficiente alfa de Cronbach para estimar la confiabilidad de la medida y el coefi ciente de correlación de Pearson (r) para evaluar la validez concurrente. Laprueba de la t de Student arrojó valores de significación estadística en las 29 preguntas; el análisis factorial exploratorio aportó cuatro factores con valores propios superiores a 1, que explican 50,93% de la varianza total; el coeficiente alfa de Cronbach para el instrumento en su conjunto fue de 0,86; finalmente, el coeficiente r de Pearson arrojó correlaciones entre las cuatro dimensiones entre sí, al igual que entre las dimensiones salud física y problemas agudos con carga viral, salud física y problemas crónicos con carga viral, así como habilidades sociales y personales con tiempo de infección en meses. El instrumento posee propiedades psicométricas de validez de constructo y validez concurrente, así como un buen nivel de confiabilidad.

Between May 2006 and April 2007 a cross-sectional study was made, with the main objective to prove the psychometric properties of an instrument to assess quality of life in persons with HIV. 149 persons withHIV participated who were being treated in two health facilities from two cities at the northwest of Mexico, whom responded to a self-administered instrument to assess quality of life in three domains: physical health, psychological health, and personal and social abilites. Four procedures of data analysis were used: the ttest for comparison of means, for assessing the comprehensibility of the questions; an exploratory factorial analysis with varimax rotation for determining construct validity; Cronbach’s alpha coeffi cient for determining reliability, and the Pearson’s correlation coeffi cient (r) for assessing concurrent validity. In all questions the t-test for comparison of means gave statistical signifi cance. A four-factor structure was found with the factorial analysis with varimax rotation, with eigen values above 1, that taken as a whole explain 50.93% of the total variance; an overall Cronbach’s alpha coefficient of 0.86 was obtained with the test of reliability. Thetest for concurrent validity showed correlations between the four-factors, as well as between the physical and acute problems with viral load, physical and chronic problems with viral load, and personal and social abilites with length of infection in months. According to the results obtained, the instrument has optimal reliability as well as construct validity and concurrent validity.

[Epidemiologic and situational panorama of hepatitis C in Mexico]. / Panorama epidemiológico y situacional de la hepatitis C en México.

OBJECTIVE: To determine the epidemiological situation of Chronic Hepatitis C (CHC) in our country. BACKGROUND DATA: Chronic Hepatitis C affects 170 million people worldwide, and about 0.7% of Mexican population. There is no enough epidemiological information about CHC in our country, and it is very probable that some cases are not even detected. METHODS: An investigation poll was performed. Age, gender, birthday, weight, race, residence and birth place, routes of transmission, ALT levels, histological, serological and molecular diagnosis, evidence of complications and previous treatments were recorded. A data recollection sheet was dispatched to different country provinces; they had 6 months to answer it, in order to recollect all information. RESULTS: 831 patients were analized (58.6% female and 41.4% male) with the following distribution in our country provinces: Aguascalientes 15, Chihuahua 12, Distrito Federal 495, Durango 10, Jalisco 89, Guanajuato 78, Yucatán 8, Querétaro 11, Sonora 40, Tabasco 15, Baja California 5, Veracruz 13, Tamaulipas 2 and 38 patients of Nuevo León. The highest incidence of CHC was found at fifth and sixth decade of life (28.5% y 26.7% respectively. The weight distribution was 36.2% < 65kg, 34.6% 65-75 kg and 29.2% > 75 kg. 86.5% had chronic hepatitis and 13.2% cirrhosis. The risk factors for HCV infection analysis showed that the main route of transmission was via contaminated blood (64.2%); when we excluded the patients that were exposed before 1995, the incidence was lowered to 4.5%. The higher incidence was showed between 1970 and 1990 (68%). The intravenous drug users were predominantly male and on those patients in the provinces near the north border line of our country. The predominant genotype was gen- 1 no matter the province (72.2%), in the intravenous drug users genotype 3 was found in 25%. The viral load was similar in all the provinces. 75% of the patients had have treatment and 22.5% had have two cycles, 50% of cirrhotic patients had have treatment whereas only 28% of the patients with late complications had have it. The most common treatment was pegylated alpha-2a interferon plus ribavirine. CONCLUSIONS: 1. The main route of transmission was blood transfusion. There is a marked decrease in the incidence of post-transfusional hepatitis since the introduction of anti-VHC antibody screening of blood donors (4.5%). 2. The time between the infection and diagnosis was 23 years for chronic hepatitis and 26 years for cirrhosis. 3. Intravenous drugs use was an important route of transmission in the north of our country. 4. The predominant genotype was gen-1. 5. Almost all the patients with chronic hepatitis received treatment, the most common used was pegylated interferon alpha-2a and ribavirin. 6.50% of the patients with CHC have late complications.