Seroprevalencia de VIH en población mexicana de entre 15 y 49 años: resultados de la Ensanut 2012 / HIV seroprevalence among Mexicans age 15 to 49: results from the National Health & Nutrition Survey 2012

Objetivo. Estimar la seroprevalencia de VIH en población mexicana no institucionalizada de 15 a 49 años, y aspectos selectos del perfil de la población serorreactiva. Material y métodos. Estudio transversal con una muestra probabilística de la población del país de 15 a 49 años, con información sobre comportamientos obtenida por entrevista directa en los hogares y determinación de anticuerpos para VIH en sangre capilar. Resultados. Se identificó una seroprevalencia de 0.15% (IC95% 0.09-0.21) en la población de 15 a 49 años; de 0.07% (IC95% 0.03-0.11) en mujeres, y de 0.24% (IC95% 0.11-0.36) en hombres. La población serorreactiva a VIH son hombres jóvenes, de mayor nivel socioeconómico en relación con la población general y con información que sugiere una mayor cobertura por la seguridad social (49.9% en serorreactivos contra 34.5% en no serorreactivos). El 49.4% de los serorreactivos contra 18.5% de los no serorreactivos se había realizado al menos una prueba de detección de VIH. Conclusiones. La seroprevalencia de VIH estimada en la Encuesta Nacional de Salud y Nutrición (Ensanut) 2012 sugiere que ésta se ha mantenido relativamente estable desde 2000. La estimación representa alrededor de 104000 personas (rango de entre 53000 y 126000) de 15 a 49 años que viven con VIH en México (75% de los cuales son hombres), de los que 50.6% desconocería su estatus serológico. Implementando un modelo de corrección de sesgo y agregando a los estimados en hogar, los casos estimados entre población de hombres que tienen sexo con hombres (tanto homosexual como bisexual), la estimación de la seroprevalencia alcanzaría 0.23%, con un total de 140000 personas de 15 a 49 años viviendo con VIH (con un intervalo estimado de entre 92000 y 201000 personas).

Objective. To estimate the HIV seroprevalence among Mexicans aged 15 to 49 years old and living in households, and to describe the profile of serorreactive individuals. Materials and methods. Cross-sectional study with a national probabilistic sample of individuals aged 15 to 49 years with behavioral data from direct interview (face-to-face) at households and HIV screening using capillary blood collected from the same individuals. Results. A seroprevalence of 0.15% (95%CI 0.09-0.21) was estimated for Mexicans aged 15 to 49; seroprevalence among women was 0.07% (95%CI 0.03-0.11) and 0.24% (95%CI 0.11-0.36) for men. HIV serorreactive population is composed of younger men, with a higher socioeconomic level compared to the general population, and with a higher insurance coverage-social protection on health in general and social security in particular. Only 50% of the serorreactive individuals may be aware of their status as living with HIV. Conclusions. The estimated HIV seroprevalence in the NHNS 2012 suggests a stable pattern since 2000. The estimated prevalence among individuals 15 to 49 years was adjusted both for selection bias correction and to include MSM estimations (under the assumption that MSM is a population hard to reach in a household survey), resulting in a total seroprevalence of 0.23% and an estimated number of people with HIV of 140000.

[HIV seroprevalence among Mexicans age 15 to 49: results from the National Health & Nutrition Survey 2012]. / Seroprevalencia de VIH en población mexicana de entre 15 y 49 años: resultados de la Ensanut 2012.

OBJECTIVE: To estimate the HIV seroprevalence among Mexicans aged 15 to 49 years old and living in households, and to describe the profile of serorreactive individuals. MATERIALS AND METHODS: Cross-sectional study with a national probabilistic sample of individuals aged 15 to 49 years with behavioral data from direct interview (face-to-face) at households and HIV screening using capillary blood collected from the same individuals. RESULTS: A seroprevalence of 0.15% (95%CI 0.09-0.21) was estimated for Mexicans aged 15 to 49; seroprevalence among women was 0.07% (95%CI 0.03-0.11) and 0.24% (95%CI 0.11-0.36) for men. HIV serorreactive population is composed of younger men, with a higher socioeconomic level compared to the general population, and with a higher insurance coverage-social protection on health in general and social security in particular. Only 50% of the serorreactive individuals may be aware of their status as living with HIV. CONCLUSIONS: The estimated HIV seroprevalence in the NHNS 2012 suggests a stable pattern since 2000. The estimated prevalence among individuals 15 to 49 years was adjusted both for selection bias correction and to include MSM estimations (under the assumption that MSM is a population hard to reach in a household survey), resulting in a total seroprevalence of 0.23% and an estimated number of people with HIV of 140,000.

[Guideline for interpretation and report of the antibody to hepatitis C virus. Grupo de Desarrollo de la Guía ]. / Guía de interpretación y reporte del anticuerpo a hepatitis C.

Patients with hepatitis C virus (HCV) infection are detected by testing for the presence of antibodies to HCV (Anti-HCV). A positive Anti-HCV test represents a true positive result only in a variable proportion of subjects (35 to 95%). The qualitative interpretation as positive or negative Anti-HCV report is associated with a general lack of understanding regarding the interpretation of results, when more specific testing should be performed, and which tests should be considered for this purpose. Therefore, a substantial variation in supplemental testing practices exists among laboratories and physicians. This guideline was developed on the basis of the best available evidence to classify positive antibody in two (low and high) or three levels (very low, low and high) according to the signal to cutoff (S/CO) ratio: the very low level of the Anti-HCV identifies false-positive results and further diagnostic testing is not necessary. The low antibody level is frequently related with false-positive results and testing with Immunoblot is recommended; only Immunoblot-positive subjects require HCV RNA testing because of a low possibility of being viremic. The high Anti-HCV level is an accurate serological marker for predicting viremia and denotes the need of routine HCV RNA testing in order to efficiently confirm hepatitis C. Cost-effectiveness analysis, based on the Anti-HCV level, recommends the use of the two or three-levels to choose the confirmatory test of positive antibody. This approach can be implemented without increasing test costs because the S/CO ratio is automatically generated in most laboratory analyzers and would provide health care professionals with useful information for counseling and evaluating patients, to eliminate unwarranted notifications in cases of false antibody reactivity, and correctly identifying those Anti-HCV-positive patients who are infected and need antiviral treatment. The written report should include the antibody level (S/CO ratio), the type of the immunoassay applied and interpretation guideline. Anti-HCV testing is performed in multiple settings including blood banks or health department facilities; adoption of this Guideline for interpretation and report of the antibody to hepatitis C virus by laboratories and its implementation by clinicians will improve the accuracy for interpreting antibody result to determine the next step on hepatitis C diagnosis.

Seroepidemiología de la hepatitis A en México: sensor de inequidad social e indicador de políticas de vacunación / Seroepidemiology of hepatitis A in Mexico: a detector of social inequity and monitor of immunization policies

OBJETIVO: Estudiar la distribución y frecuencia de los anticuerpos contra el virus de la hepatitis A en una muestra probabilística en México con representatividad estatal, así como analizar los factores de riesgo y los patrones epidemiológicos. MATERIAL Y MÉTODOS: A partir de la Encuesta Nacional de Salud se estudiaron 4 907 sueros seleccionados de forma aleatoria para anticuerpos contra VHA mediante ensayo inmunoenzimático. Los sueros se recolectaron de noviembre de 1999 a junio del 2000 a nivel nacional. RESULTADOS: Se encontró seroprevalencia general de 81.3 por ciento (IC 78.6-84.2), y los resultados expandidos permiten inferir que existen 78.7 millones de mexicanos infectados. Los factores de riesgo en menores de nueve años incluyen residir en entidades sureñas (RM= 5.3), localidades rurales (RM= 3.1), provenir de familia con bajos ingresos (RM= 2.4) y habitar viviendas con acceso limitado a servicios sanitarios (agua, RM= 2.5; drenaje, RM= 2.7). CONCLUSIONES: Los patrones de transmisión heterogéneos y las diferencias en las pre-valencias de infección indican inequidad en las poblaciones estudiadas, explicables por diferencias en las condiciones sanitarias y sociales. Se discuten las ventajas de intervenciones poblacionales tales como la vacunación y el fortalecimiento de las condiciones sanitarias y socioeconómicas.

OBJECTIVE: Hepatitis A Virus (HAV) in Mexico has traditionally been considered a disease with a homogeneous pattern of transmission, high rates of infection at early ages, and infrequent complication rates. The purpose of this study was to take advantage of the 2000 NHS, a probabilistic population-based survey, in order to describe the seroepidemiology of HAV infection in Mexico. MATERIAL AND METHODS: This study is based on information obtained from the National Health Survey that was conducted in 2000. The present report is based on 4 907 randomly selected samples that were studied to determine the prevalence of HAV antibodies using immunoenzymatic assay. Sera were collected from November 1999 to June 2000. RESULTS: Seroprevalence among the general population was 81.3 percent (CI95 percent: 78.6-84.2); expanded results allow the inference that 78.7 million Mexicans have been infected by this agent. Risk factors for HAV among children younger than nine years of age are the following: residence in southern states OR=5.3, residence in rural communities OR= 3.1, low-income family OR= 2.4 and living in households with limited access to sanitary facilities (water OR= 2.5 and sewage OR= 2.7). CONCLUSIONS: Results of this study demonstrate that HAV transmission patterns are heterogeneous and that differentials in the prevalence of infection are due to sanitary and social inequity among studied populations. Finally, the advantages of adopting public health measures such as vaccination and improvement of sanitary and socioeconomic conditions are discussed.