Impact of a quadrivalent HPV6/11/16/18 vaccine in Mexican women: public health implications for the region.

BACKGROUND AND AIMS: Recognition of human papillomavirus (HPV) as a necessary cause of cervical cancer (CC) led to new perspectives for its control and the demonstration of an effective primary prevention strategy through vaccination. We undertook this study to evaluate the safety, efficacy and immunogenicity of a quadrivalent HPV6/11/16/18 vaccine in Mexican women. METHODS: A total of 679 Mexican women between 18 and 23 years old participated in two Phase III double-blind, randomized, placebo-controlled clinical trials of a quadrivalent HPV 6/11/16/18 vaccine. Women were enrolled who tested negative for pregnancy and reported having four or less sexual partners during their lifetime. Vaccine or placebo was administered at day 1, month 2 and month 6. RESULTS: Among Mexican women who were naïve to the respective vaccine type at enrollment, the quadrivalent vaccine was highly efficacious, preventing 100% of HPV6/11/16/18-related cervical intraepithelial neoplasia grade 2/3, adenocarcinoma in situ, condyloma and vaginal intraepithelial neoplasia. Statistical significance was not reached for every endpoint due to the limited sample size. Vaccination was generally well tolerated and immunogenic. DISCUSSION: To widely administer the vaccine, collaborative efforts should be coordinated among public, private and local community sectors. In light of the scarce knowledge of many health professionals with respect to the primary prevention of CC, it will be necessary to educate health providers on the advantages and specific recommendations of HPV vaccines and secondary prevention. Decision making should be based on scientific evidence, allowing health professionals to provide an organized social response that supports the universal right to health.

Strategies and ethical considerations for the recruitment of young men who have sex with men: challenges of a vaccination trial in Mexico.

BACKGROUND: The importance of recruiting and retaining study participants from minority groups is well recognized; however, there are no established rules for recruitment as its success depends on the setting and population. PURPOSE: To describe and analyze recruitment strategies, ethical considerations, and recruitment outcomes from a study to evaluate the efficacy the Human Papilloma Virus vaccine in young men who have sex with men (MSM). METHODS: The recruitment settings were university and community sites in the state of Morelos, Mexico. Eligibility requirement were men between 18 and 23 years old, who were free of anal-genital lesions as confirmed by clinical exploration, HIV negative, with no history of sexual relations with female partners and with fewer than five male lifetime sexual partners. Recruitment goals were 25 study participants in a four and a half month period. In addition to traditional recruitment strategies (flyers and media advertising, specific training of the recruitment team and adequate choice of recruitment sites)-engagement of local leaders in the MSM community formed a crucial part of the strategy. Special consideration was given to confidentiality and respect for study participants and a Bill of Participant Rights was developed as an explicit commitment to respect and acceptance. RESULTS: In total 723 MSM were initially contacted, 243 filled out the recruitment questionnaire, of which 151 met the criteria to be invited to the clinical examination. After clinical examination and interviews with the recruitment team, 131 fulfilled the inclusion criteria, of whom 73 were enrolled in the study - nearly triple the recruitment goal. Among the initial recruitment strategies (application of the screening questionnaire) attending meetings with MSM activist organizations was the most successful (326), followed by recruitment at bars and dance clubs (107). LIMITATIONS: The recruitment strategies should be formally evaluated for their effectiveness to identify those which are most successful. In addition, future studies should consider the evaluation of study participants' perceptions of the recruitment strategies. CONCLUSIONS: Recruiting MSM in a developing country such as Mexico presented multiple challenges. We recommend that future studies actively engage the local MSM community and pay special attention to designing recruitment strategies that guarantee the confidentiality of and respect for participants.

Concordancia entre observadores en la evaluación de protocolos de investigación clínica / The agreement between observators in evaluation of clinical research protocols

Objetivo: Determinar el nivel de concordancia entre los integrantes de la Unidad de Epidemiología Clínica en la evaluación de aspectos metodológicos de los protocolos de investigación clínica. Material y métodos: Se seleccionaron aleatoriamente 15 protocolos de investigación registrados durante 1992 en el Hospital General de México, y fueron evaluados por ocho observadores de la Unidad de Epidemiología Clínica siguiéndose un formato diseñado para el estudio. Cada protocolo fue calificado en tres escalas: 1) aprobado/rechazado, 2) escala ordinal de cuatro categorías de la calidad metodológica y 3) puntaje detallado que calificaba cada uno de los aspectos del estudio: Cada protocolo fue independientemente evaluado por todos los observadores. Análisis: Se calcularon coeficientes Kappa y Kappa ponderada entre las parejas de observadores y el coeficiente de correlación intraclase en las calificaciones de los protocolos. Resultados: Se observó una concordancia regular en las parejas de observadores al aprobar o rechazar un protocolo. Las concordancias en la escala de cuatro puntos fueron diversas: buena en cinco parejas y moderada a baja en 11. La concordancia del puntaje total fue excelente. Conclusiones: Los resultados preliminares sugieren que la evaluación objetiva y estandarizada de los protocolos de investigación, utilizando criterios de rigidez científica disminuiría sesgos del evaluador y mejorarían la calidad de presentación de los mismos

Tomografía axial y resonancia magnética en la patología del mediastino / Computed tomography and magnetic resonance imaging in the pathology of mediastinum

Se analizó la utilidad de la tomografía Axial Computada (TC) y de la imagen de Resonancia magnética (RM) en la evaluación de las lesiones ocupativas del mediastino. Se estudiaron 30 pacientes con ensanchamiento del mediastino detectado en radiografías simples (tórax PA y lateral). Se realizaron TC y RM en todos los casos. 23 pacientes (80 por ciento) tenían procesos mediastinales ocupativos diversos. Se excluyeron cinco que tuvieron patología vascular y dos en los cuales el ensanchamiento aparente del mediatino era secundario a una hernia de Morgagni. Se valoró la utilidad de ambos métodos de imagen en la determinación de localización, extensión, invasión y naturaleza tisular de las lesiones mediastinales, en relación con los hallazgos quirúrgicos y con el diagnóstico histopatológico en todos los casos y con la información obtenida por los métodos de imagen. La información proporcionada por estos métodos en cuanto a la localización de las lesiones fue similar; la RM fue superior para conocer la extensión de los diferentes procesos hacia las estructuras adyacentes y para determinar la invasión a estructuras vasculares y pared torácica, lo que permitió planear las posibilidades de la resección qurúrgica con gran precisión. La correlación de la caracterización histológica obtenida mediante los métodos de imagen con el diagnóstico histológico definitivo dió una precisión de 78 por ciento para ambos métodos