Prevalencia de leptospirosis en adultos Chile, 2003 / Prevalence of leptospirosis in adults in Chile, 2003

Background: Leptospirosis is a zoonosis endemic in some regions in Chile. Since its inclusion into the list of notifiable diseases, the Chilean Ministry of Health was able to maintain an adequate surveillance of leptospirosis. Nonetheless, some cases are not reported due to subclinical disease or nonspecific symptoms. Objectives: Determine the national prevalence of leptospirosis and assess the epidemiological characteristics of seropositive individuals. Methods: Secondary data analysis of the National Health Survey, 2003. Results: National prevalence was 0.4%. Low socioeconomical status and female gender were characteristics, which were more frequently found in sero-positive cases. The most common serovars were icterohaemorrhagiae, bratislava and pomona. Conclusion: We present the first epidemiological analysis of leptospirosis on a national level in Chile. Thus, the study contributes to the knowledge the epidemiological situation of this disease in Chile.

Introducción: La leptospirosis es una zoonosis endémica en ciertas regiones de Chile. Desde que se incorporó esta enfermedad en la lista de las Enfermedades de Notificación Obligatoria (ENO) se ha logrado mantener una adecuada vigilancia. Sin embargo, existen casos subclínicos y con manifestaciones inespecíficas que no son reportados. Objetivo: Determinar la prevalencia nacional de leptospirosis y conocer características epidemiológicas de individuos seropositivos. Material y Métodos: Análisis de datos secundarios obtenidos en la Encuesta Nacional de Enfermedades Prioritarias, 2003. Resultados: La prevalencia nacional de leptospirosis fue 0,4%. Las características que se identificaron con mayor frecuencia en el grupo de personas positivas fueron nivel socio-económico bajo y sexo femenino. Los serovares más frecuentes fueron icterohaemorrhagiae, bratislava y pomona. Conclusión: Este es el primer trabajo de prevalencia nacional de leptospirosis realizado en Chile. Este estudio aporta al diagnóstico de situación de esta patología en nuestro país.

[Prevalence of leptospirosis in adults in Chile, 2003]. / Prevalencia de leptospirosis en adultos Chile, 2003.

BACKGROUND: Leptospirosis is a zoonosis endemic in some regions in Chile. Since its inclusion into the list of notifiable diseases, the Chilean Ministry of Health was able to maintain an adequate surveillance of leptospirosis. Nonetheless, some cases are not reported due to subclinical disease or nonspecific symptoms. OBJECTIVES: Determine the national prevalence of leptospirosis and assess the epidemiological characteristics of seropositive individuals. METHODS: Secondary data analysis of the National Health Survey, 2003. RESULTS: National prevalence was 0.4%. Low socioeconomical status and female gender were characteristics, which were more frequently found in sero-positive cases. The most common serovars were icterohaemorrhagiae, bratislava and pomona. CONCLUSION: We present the first epidemiological analysis of leptospirosis on a national level in Chile. Thus, the study contributes to the knowledge the epidemiological situation of this disease in Chile.

[Hepatitis A and E virus antibodies in Chilean children of low socioeconomic status: a one year follow-up study]. / Seguimientos de anticuerpos contra hepatitis A y E en una cohorte de niños de bajo nivel socioeconómico.

BACKGROUND: The seroprevalence of antibodies against hepatitis A virus (HAV) is decreasing in many Latin American countries, along with improvements in sanitary standards. However, there is no information available about low socioeconomic status (LSE) populations. AIM: To assess the evolution of hepatitis A and E virus antibodies in a cohort of LSE Chilean children. MATERIAL AND METHODS: One hundred sixty eight children aged four years, 97 males, coming from public primary care clinics, were studied. Two blood samples were obtained with an interval of one year. Anti-HAV and anti-hepatitis E virus (HEV) antibodies, were detected by ELISA using Abbott kits. RESULTS: Anti-HAV was positive in 19 children (11.3%). After one year of follow-up, only 10 children had sustained reactivity (52.6%). Fourteen children, initially negative, became positive during the follow up (9.4%). Antibody titers to HAV were significantly higher in samples that remained positive, compared with those that lost reactivity. Anti-HEV was found positive in two children (1.2%). One remained positive and the other became negative. CONCLUSIONS: In this cohort of LSE Chilean children, the prevalence to antibodies against HAV and HEV is low. Follow-up detected loss of reactivity to HAV in nearly one half of the children, probably related to lower antibody levels.

Facilitating the WHO expanded program of immunization: the clinical profile of a combined diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type b vaccine.

BACKGROUND: Vaccines are important weapons in the fight against infectious diseases. The World Health Organization (WHO) Expanded Program on Immunization (EPI) has been extended to include recommendations for hepatitis B and Haemophilus influenzae type b (Hib) vaccinations. The WHO has recommended that combined vaccines be used where possible, to reduce the logistic costs of vaccine delivery. This paper reviews the efficacy, safety and cost-effectiveness of Tritanrix-HB/Hib, the only commercially available combined diphtheria, tetanus, whole cell pertussis, hepatitis B and conjugated Hib vaccine. METHODS: The immunogenicity and reactogenicity results of five published clinical trials involving Tritanrix-HB/Hib in a variety of immunization schedules and countries were reviewed. Based on these data and cost-effectiveness studies, an assessment of its suitability for use in national immunization programs was made. RESULTS: Tritanrix-HB/Hib has shown excellent immunogenicity in clinical trials using a variety of schedules, with no reduced immunogenicity observed for any of the components of the combined vaccine. It has similar reactogenicity to DTPw vaccines alone. Pharmacoeconomic analyses have shown combined DTP-HB/Hib vaccines to be cost-effective compared to separate vaccines. CONCLUSIONS: Replacement of DTPw vaccination by Tritanrix-HB/Hib can be done without modifying the existing national immunization programs. This should facilitate widespread coverage of hepatitis B and Hib vaccinations and their rapid incorporation into the EPI.

Immunogenicity and reactogenicity of combined versus separately administered DTPw-HBV and Hib vaccines given to healthy infants at 2, 4 and 6 months of age, with a booster at 18 months.

OBJECTIVES: To determine the immunogenicity and reactogenicity of a combined DTPw-HBV/Hib vaccine, in comparison with DTPw-HBV and Hib vaccines given as separate concomitant injections. METHODS: In an open, randomized study, healthy infants were injected with either DTPw-HBV/Hib vaccine or separate DTPw-HBV and Hib vaccines at 2, 4 and 6 months of age, with a booster at 18 months. RESULTS: Both vaccination regimens were immunogenic, with seropositivity rates of 100% after the booster vaccination for all vaccine components. Even as early as 2 months after the second dose of the primary vaccination, most patients had seroprotective antibody titers, the proportion of seropositive subjects approaching 100% for tetanus, hepatitis B, and Hib. Post-primary and post-booster geometric mean titers (GMTs) were well above seroprotective thresholds for each vaccine antigen in both groups, with no clinically relevant differences in the groups. The separate and combined administrations showed comparable reactogenicity profiles, and neither showed a significant increase in reactogenicity with successive doses. CONCLUSIONS: The results of this study support the combination of Hib and DTPw-HBV vaccination in routine infant immunization at 2, 4 and 6 months of age with a booster at 18 months. Maximum benefit is obtained from compliance with the full course, but substantial benefit is likely to be achieved even in partially compliant patients, provided they receive at least two doses. Furthermore, these results demonstrate the tolerability of a fourth (booster) administration, where the addition of the Hib vaccine to DTPw-HBV did not lead to an increase in the overall reactogenicity.